v4.19.13 snapshot.
diff --git a/tools/build/.gitignore b/tools/build/.gitignore
new file mode 100644
index 0000000..a776371
--- /dev/null
+++ b/tools/build/.gitignore
@@ -0,0 +1 @@
+fixdep
diff --git a/tools/build/Build b/tools/build/Build
new file mode 100644
index 0000000..76d1a49
--- /dev/null
+++ b/tools/build/Build
@@ -0,0 +1,3 @@
+hostprogs := fixdep
+
+fixdep-y := fixdep.o
diff --git a/tools/build/Build.include b/tools/build/Build.include
new file mode 100644
index 0000000..9ec01f4
--- /dev/null
+++ b/tools/build/Build.include
@@ -0,0 +1,101 @@
+###
+# build: Generic definitions
+#
+#  Lots of this code have been borrowed or heavily inspired from parts
+#  of kbuild code, which is not credited, but mostly developed by:
+#
+#  Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
+#  Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
+#
+
+###
+# Convenient variables
+comma   := ,
+squote  := '
+pound   := \#
+
+###
+# Name of target with a '.' as filename prefix. foo/bar.o => foo/.bar.o
+dot-target = $(dir $@).$(notdir $@)
+
+###
+# filename of target with directory and extension stripped
+basetarget = $(basename $(notdir $@))
+
+###
+# The temporary file to save gcc -MD generated dependencies must not
+# contain a comma
+depfile = $(subst $(comma),_,$(dot-target).d)
+
+###
+# Check if both arguments has same arguments. Result is empty string if equal.
+arg-check = $(strip $(filter-out $(cmd_$(1)), $(cmd_$@)) \
+                    $(filter-out $(cmd_$@),   $(cmd_$(1))) )
+
+###
+# Escape single quote for use in echo statements
+escsq = $(subst $(squote),'\$(squote)',$1)
+
+# Echo command
+# Short version is used, if $(quiet) equals `quiet_', otherwise full one.
+echo-cmd = $(if $($(quiet)cmd_$(1)),\
+           echo '  $(call escsq,$($(quiet)cmd_$(1)))';)
+
+###
+# Replace >$< with >$$< to preserve $ when reloading the .cmd file
+# (needed for make)
+# Replace >#< with >$(pound)< to avoid starting a comment in the .cmd file
+# (needed for make)
+# Replace >'< with >'\''< to be able to enclose the whole string in '...'
+# (needed for the shell)
+make-cmd = $(call escsq,$(subst $(pound),$$(pound),$(subst $$,$$$$,$(cmd_$(1)))))
+
+###
+# Find any prerequisites that is newer than target or that does not exist.
+# PHONY targets skipped in both cases.
+any-prereq = $(filter-out $(PHONY),$?) $(filter-out $(PHONY) $(wildcard $^),$^)
+
+###
+# Copy dependency data into .cmd file
+#  - gcc -M dependency info
+#  - command line to create object 'cmd_object :='
+dep-cmd = $(if $(wildcard $(fixdep)),                                           \
+           $(fixdep) $(depfile) $@ '$(make-cmd)' > $(dot-target).tmp;           \
+           rm -f $(depfile);                                                    \
+           mv -f $(dot-target).tmp $(dot-target).cmd,                           \
+           printf '$(pound) cannot find fixdep (%s)\n' $(fixdep) > $(dot-target).cmd; \
+           printf '$(pound) using basic dep data\n\n' >> $(dot-target).cmd;           \
+           cat $(depfile) >> $(dot-target).cmd;                                 \
+           printf '\n%s\n' 'cmd_$@ := $(make-cmd)' >> $(dot-target).cmd)
+
+###
+# if_changed_dep  - execute command if any prerequisite is newer than
+#                   target, or command line has changed and update
+#                   dependencies in the cmd file
+if_changed_dep = $(if $(strip $(any-prereq) $(arg-check)),         \
+                  @set -e;                                         \
+                  $(echo-cmd) $(cmd_$(1)) && $(dep-cmd))
+
+# if_changed      - execute command if any prerequisite is newer than
+#                   target, or command line has changed
+if_changed = $(if $(strip $(any-prereq) $(arg-check)),                   \
+              @set -e;                                                   \
+              $(echo-cmd) $(cmd_$(1));                                   \
+              printf '%s\n' 'cmd_$@ := $(make-cmd)' > $(dot-target).cmd)
+
+###
+# C flags to be used in rule definitions, includes:
+# - depfile generation
+# - global $(CFLAGS)
+# - per target C flags
+# - per object C flags
+# - BUILD_STR macro to allow '-D"$(variable)"' constructs
+c_flags_1 = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CFLAGS) -D"BUILD_STR(s)=\#s" $(CFLAGS_$(basetarget).o) $(CFLAGS_$(obj))
+c_flags_2 = $(filter-out $(CFLAGS_REMOVE_$(basetarget).o), $(c_flags_1))
+c_flags   = $(filter-out $(CFLAGS_REMOVE_$(obj)), $(c_flags_2))
+cxx_flags = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(CXXFLAGS) -D"BUILD_STR(s)=\#s" $(CXXFLAGS_$(basetarget).o) $(CXXFLAGS_$(obj))
+
+###
+## HOSTCC C flags
+
+host_c_flags = -Wp,-MD,$(depfile) -Wp,-MT,$@ $(KBUILD_HOSTCFLAGS) -D"BUILD_STR(s)=\#s" $(HOSTCFLAGS_$(basetarget).o) $(HOSTCFLAGS_$(obj))
diff --git a/tools/build/Documentation/Build.txt b/tools/build/Documentation/Build.txt
new file mode 100644
index 0000000..a225874
--- /dev/null
+++ b/tools/build/Documentation/Build.txt
@@ -0,0 +1,168 @@
+Build Framework
+===============
+
+The perf build framework was adopted from the kernel build system, hence the
+idea and the way how objects are built is the same.
+
+Basically the user provides set of 'Build' files that list objects and
+directories to nest for specific target to be build.
+
+Unlike the kernel we don't have a single build object 'obj-y' list that where
+we setup source objects, but we support more. This allows one 'Build' file to
+carry a sources list for multiple build objects.
+
+
+Build framework makefiles
+-------------------------
+
+The build framework consists of 2 Makefiles:
+
+  Build.include
+  Makefile.build
+
+While the 'Build.include' file contains just some generic definitions, the
+'Makefile.build' file is the makefile used from the outside. It's
+interface/usage is following:
+
+  $ make -f tools/build/Makefile.build srctree=$(KSRC) dir=$(DIR) obj=$(OBJECT)
+
+where:
+
+  KSRC   - is the path to kernel sources
+  DIR    - is the path to the project to be built
+  OBJECT - is the name of the build object
+
+When succefully finished the $(DIR) directory contains the final object file
+called $(OBJECT)-in.o:
+
+  $ ls $(DIR)/$(OBJECT)-in.o
+
+which includes all compiled sources described in 'Build' makefiles.
+
+
+Build makefiles
+---------------
+
+The user supplies 'Build' makefiles that contains a objects list, and connects
+the build to nested directories.
+
+Assume we have the following project structure:
+
+  ex/a.c
+    /b.c
+    /c.c
+    /d.c
+    /arch/e.c
+    /arch/f.c
+
+Out of which you build the 'ex' binary ' and the 'libex.a' library:
+
+  'ex'      - consists of 'a.o', 'b.o' and libex.a
+  'libex.a' - consists of 'c.o', 'd.o', 'e.o' and 'f.o'
+
+The build framework does not create the 'ex' and 'libex.a' binaries for you, it
+only prepares proper objects to be compiled and grouped together.
+
+To follow the above example, the user provides following 'Build' files:
+
+  ex/Build:
+    ex-y += a.o
+    ex-y += b.o
+    ex-y += b.o # duplicates in the lists are allowed
+
+    libex-y += c.o
+    libex-y += d.o
+    libex-y += arch/
+
+  ex/arch/Build:
+    libex-y += e.o
+    libex-y += f.o
+
+and runs:
+
+  $ make -f tools/build/Makefile.build dir=. obj=ex
+  $ make -f tools/build/Makefile.build dir=. obj=libex
+
+which creates the following objects:
+
+  ex/ex-in.o
+  ex/libex-in.o
+
+that contain request objects names in Build files.
+
+It's only a matter of 2 single commands to create the final binaries:
+
+  $ ar  rcs libex.a libex-in.o
+  $ gcc -o ex ex-in.o libex.a
+
+You can check the 'ex' example in 'tools/build/tests/ex' for more details.
+
+
+Makefile.include
+----------------
+
+The tools/build/Makefile.include makefile could be included
+via user makefiles to get usefull definitions.
+
+It defines following interface:
+
+  - build macro definition:
+      build := -f $(srctree)/tools/build/Makefile.build dir=. obj
+
+    to make it easier to invoke build like:
+      make $(build)=ex
+
+
+Fixdep
+------
+It is necessary to build the fixdep helper before invoking the build.
+The Makefile.include file adds the fixdep target, that could be
+invoked by the user.
+
+
+Rules
+-----
+
+The build framework provides standard compilation rules to handle .S and .c
+compilation.
+
+It's possible to include special rule if needed (like we do for flex or bison
+code generation).
+
+
+CFLAGS
+------
+
+It's possible to alter the standard object C flags in the following way:
+
+  CFLAGS_perf.o        += '...'  - adds CFLAGS for perf.o object
+  CFLAGS_gtk           += '...'  - adds CFLAGS for gtk build object
+  CFLAGS_REMOVE_perf.o += '...'  - removes CFLAGS for perf.o object
+  CFLAGS_REMOVE_gtk    += '...'  - removes CFLAGS for gtk build object
+
+This C flags changes has the scope of the Build makefile they are defined in.
+
+
+Dependencies
+------------
+
+For each built object file 'a.o' the '.a.cmd' is created and holds:
+
+  - Command line used to built that object
+    (for each object)
+
+  - Dependency rules generated by 'gcc -Wp,-MD,...'
+    (for compiled object)
+
+All existing '.cmd' files are included in the Build process to follow properly
+the dependencies and trigger a rebuild when necessary.
+
+
+Single rules
+------------
+
+It's possible to build single object file by choice, like:
+
+  $ make util/map.o    # objects
+  $ make util/map.i    # preprocessor
+  $ make util/map.s    # assembly
diff --git a/tools/build/Makefile b/tools/build/Makefile
new file mode 100644
index 0000000..727050c
--- /dev/null
+++ b/tools/build/Makefile
@@ -0,0 +1,50 @@
+# SPDX-License-Identifier: GPL-2.0
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+endif
+
+include $(srctree)/tools//scripts/Makefile.include
+
+define allow-override
+  $(if $(or $(findstring environment,$(origin $(1))),\
+            $(findstring command line,$(origin $(1)))),,\
+    $(eval $(1) = $(2)))
+endef
+
+$(call allow-override,CC,$(CROSS_COMPILE)gcc)
+$(call allow-override,LD,$(CROSS_COMPILE)ld)
+
+HOSTCC ?= gcc
+HOSTLD ?= ld
+HOSTAR ?= ar
+
+export HOSTCC HOSTLD HOSTAR
+
+ifeq ($(V),1)
+  Q =
+else
+  Q = @
+endif
+
+export Q srctree CC LD
+
+MAKEFLAGS := --no-print-directory
+build     := -f $(srctree)/tools/build/Makefile.build dir=. obj
+
+all: $(OUTPUT)fixdep
+
+clean:
+	$(call QUIET_CLEAN, fixdep)
+	$(Q)find $(if $(OUTPUT),$(OUTPUT),.) -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
+	$(Q)rm -f $(OUTPUT)fixdep
+
+$(OUTPUT)fixdep-in.o: FORCE
+	$(Q)$(MAKE) $(build)=fixdep
+
+$(OUTPUT)fixdep: $(OUTPUT)fixdep-in.o
+	$(QUIET_LINK)$(HOSTCC) $(KBUILD_HOSTLDFLAGS) -o $@ $<
+
+FORCE:
+
+.PHONY: FORCE
diff --git a/tools/build/Makefile.build b/tools/build/Makefile.build
new file mode 100644
index 0000000..cd72016
--- /dev/null
+++ b/tools/build/Makefile.build
@@ -0,0 +1,162 @@
+# SPDX-License-Identifier: GPL-2.0
+###
+# Main build makefile.
+#
+#  Lots of this code have been borrowed or heavily inspired from parts
+#  of kbuild code, which is not credited, but mostly developed by:
+#
+#  Copyright (C) Sam Ravnborg <sam@mars.ravnborg.org>, 2015
+#  Copyright (C) Linus Torvalds <torvalds@linux-foundation.org>, 2015
+#
+
+PHONY := __build
+__build:
+
+ifeq ($(V),1)
+  quiet =
+  Q =
+else
+  quiet=quiet_
+  Q=@
+endif
+
+ifneq ($(findstring s,$(filter-out --%,$(MAKEFLAGS))),)
+  quiet=silent_
+endif
+
+build-dir := $(srctree)/tools/build
+
+# Define $(fixdep) for dep-cmd function
+ifeq ($(OUTPUT),)
+  fixdep := $(build-dir)/fixdep
+else
+  fixdep := $(OUTPUT)/fixdep
+endif
+
+# Generic definitions
+include $(build-dir)/Build.include
+
+# do not force detected configuration
+-include $(OUTPUT).config-detected
+
+# Init all relevant variables used in build files so
+# 1) they have correct type
+# 2) they do not inherit any value from the environment
+subdir-y     :=
+obj-y        :=
+subdir-y     :=
+subdir-obj-y :=
+
+# Build definitions
+build-file := $(dir)/Build
+-include $(build-file)
+
+quiet_cmd_flex  = FLEX     $@
+quiet_cmd_bison = BISON    $@
+
+# Create directory unless it exists
+quiet_cmd_mkdir = MKDIR    $(dir $@)
+      cmd_mkdir = mkdir -p $(dir $@)
+     rule_mkdir = $(if $(wildcard $(dir $@)),,@$(call echo-cmd,mkdir) $(cmd_mkdir))
+
+# Compile command
+quiet_cmd_cc_o_c = CC       $@
+      cmd_cc_o_c = $(CC) $(c_flags) -c -o $@ $<
+
+quiet_cmd_host_cc_o_c = HOSTCC   $@
+      cmd_host_cc_o_c = $(HOSTCC) $(host_c_flags) -c -o $@ $<
+
+quiet_cmd_cxx_o_c = CXX      $@
+      cmd_cxx_o_c = $(CXX) $(cxx_flags) -c -o $@ $<
+
+quiet_cmd_cpp_i_c = CPP      $@
+      cmd_cpp_i_c = $(CC) $(c_flags) -E -o $@ $<
+
+quiet_cmd_cc_s_c = AS       $@
+      cmd_cc_s_c = $(CC) $(c_flags) -S -o $@ $<
+
+quiet_cmd_gen = GEN      $@
+
+# Link agregate command
+# If there's nothing to link, create empty $@ object.
+quiet_cmd_ld_multi = LD       $@
+      cmd_ld_multi = $(if $(strip $(obj-y)),\
+                     $(LD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(AR) rcs $@)
+
+quiet_cmd_host_ld_multi = HOSTLD   $@
+      cmd_host_ld_multi = $(if $(strip $(obj-y)),\
+                          $(HOSTLD) -r -o $@  $(filter $(obj-y),$^),rm -f $@; $(HOSTAR) rcs $@)
+
+ifneq ($(filter $(obj),$(hostprogs)),)
+  host = host_
+endif
+
+# Build rules
+$(OUTPUT)%.o: %.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,$(host)cc_o_c)
+
+$(OUTPUT)%.o: %.cpp FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cxx_o_c)
+
+$(OUTPUT)%.o: %.S FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,$(host)cc_o_c)
+
+$(OUTPUT)%.i: %.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cpp_i_c)
+
+$(OUTPUT)%.s: %.S FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cpp_i_c)
+
+$(OUTPUT)%.s: %.c FORCE
+	$(call rule_mkdir)
+	$(call if_changed_dep,cc_s_c)
+
+# Gather build data:
+#   obj-y        - list of build objects
+#   subdir-y     - list of directories to nest
+#   subdir-obj-y - list of directories objects 'dir/$(obj)-in.o'
+obj-y        := $($(obj)-y)
+subdir-y     := $(patsubst %/,%,$(filter %/, $(obj-y)))
+obj-y        := $(patsubst %/, %/$(obj)-in.o, $(obj-y))
+subdir-obj-y := $(filter %/$(obj)-in.o, $(obj-y))
+
+# '$(OUTPUT)/dir' prefix to all objects
+objprefix    := $(subst ./,,$(OUTPUT)$(dir)/)
+obj-y        := $(addprefix $(objprefix),$(obj-y))
+subdir-obj-y := $(addprefix $(objprefix),$(subdir-obj-y))
+
+# Final '$(obj)-in.o' object
+in-target := $(objprefix)$(obj)-in.o
+
+PHONY += $(subdir-y)
+
+$(subdir-y):
+	$(Q)$(MAKE) -f $(build-dir)/Makefile.build dir=$(dir)/$@ obj=$(obj)
+
+$(sort $(subdir-obj-y)): $(subdir-y) ;
+
+$(in-target): $(obj-y) FORCE
+	$(call rule_mkdir)
+	$(call if_changed,$(host)ld_multi)
+
+__build: $(in-target)
+	@:
+
+PHONY += FORCE
+FORCE:
+
+# Include all cmd files to get all the dependency rules
+# for all objects included
+targets   := $(wildcard $(sort $(obj-y) $(in-target) $(MAKECMDGOALS)))
+cmd_files := $(wildcard $(foreach f,$(targets),$(dir $(f)).$(notdir $(f)).cmd))
+
+ifneq ($(cmd_files),)
+  include $(cmd_files)
+endif
+
+.PHONY: $(PHONY)
diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
new file mode 100644
index 0000000..f216b2f
--- /dev/null
+++ b/tools/build/Makefile.feature
@@ -0,0 +1,239 @@
+feature_dir := $(srctree)/tools/build/feature
+
+ifneq ($(OUTPUT),)
+  OUTPUT_FEATURES = $(OUTPUT)feature/
+  $(shell mkdir -p $(OUTPUT_FEATURES))
+endif
+
+feature_check = $(eval $(feature_check_code))
+define feature_check_code
+  feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
+endef
+
+feature_set = $(eval $(feature_set_code))
+define feature_set_code
+  feature-$(1) := 1
+endef
+
+#
+# Build the feature check binaries in parallel, ignore errors, ignore return value and suppress output:
+#
+
+#
+# Note that this is not a complete list of all feature tests, just
+# those that are typically built on a fully configured system.
+#
+# [ Feature tests not mentioned here have to be built explicitly in
+#   the rule that uses them - an example for that is the 'bionic'
+#   feature check. ]
+#
+FEATURE_TESTS_BASIC :=                  \
+        backtrace                       \
+        dwarf                           \
+        dwarf_getlocations              \
+        fortify-source                  \
+        sync-compare-and-swap           \
+        glibc                           \
+        gtk2                            \
+        gtk2-infobar                    \
+        libaudit                        \
+        libbfd                          \
+        libelf                          \
+        libelf-getphdrnum               \
+        libelf-gelf_getnote             \
+        libelf-getshdrstrndx            \
+        libelf-mmap                     \
+        libnuma                         \
+        numa_num_possible_cpus          \
+        libperl                         \
+        libpython                       \
+        libpython-version               \
+        libslang                        \
+        libcrypto                       \
+        libunwind                       \
+        libunwind-x86                   \
+        libunwind-x86_64                \
+        libunwind-arm                   \
+        libunwind-aarch64               \
+        pthread-attr-setaffinity-np     \
+        pthread-barrier     		\
+        reallocarray                    \
+        stackprotector-all              \
+        timerfd                         \
+        libdw-dwarf-unwind              \
+        zlib                            \
+        lzma                            \
+        get_cpuid                       \
+        bpf                             \
+        sched_getcpu			\
+        sdt				\
+        setns				\
+        libopencsd
+
+# FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
+# of all feature tests
+FEATURE_TESTS_EXTRA :=                  \
+         bionic                         \
+         compile-32                     \
+         compile-x32                    \
+         cplus-demangle                 \
+         hello                          \
+         libbabeltrace                  \
+         liberty                        \
+         liberty-z                      \
+         libunwind-debug-frame          \
+         libunwind-debug-frame-arm      \
+         libunwind-debug-frame-aarch64  \
+         cxx                            \
+         llvm                           \
+         llvm-version                   \
+         clang
+
+FEATURE_TESTS ?= $(FEATURE_TESTS_BASIC)
+
+ifeq ($(FEATURE_TESTS),all)
+  FEATURE_TESTS := $(FEATURE_TESTS_BASIC) $(FEATURE_TESTS_EXTRA)
+endif
+
+FEATURE_DISPLAY ?=              \
+         dwarf                  \
+         dwarf_getlocations     \
+         glibc                  \
+         gtk2                   \
+         libaudit               \
+         libbfd                 \
+         libelf                 \
+         libnuma                \
+         numa_num_possible_cpus \
+         libperl                \
+         libpython              \
+         libslang               \
+         libcrypto              \
+         libunwind              \
+         libdw-dwarf-unwind     \
+         zlib                   \
+         lzma                   \
+         get_cpuid              \
+         bpf
+
+# Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features.
+# If in the future we need per-feature checks/flags for features not
+# mentioned in this list we need to refactor this ;-).
+set_test_all_flags = $(eval $(set_test_all_flags_code))
+define set_test_all_flags_code
+  FEATURE_CHECK_CFLAGS-all  += $(FEATURE_CHECK_CFLAGS-$(1))
+  FEATURE_CHECK_LDFLAGS-all += $(FEATURE_CHECK_LDFLAGS-$(1))
+endef
+
+$(foreach feat,$(FEATURE_TESTS),$(call set_test_all_flags,$(feat)))
+
+#
+# Special fast-path for the 'all features are available' case:
+#
+$(call feature_check,all,$(MSG))
+
+#
+# Just in case the build freshly failed, make sure we print the
+# feature matrix:
+#
+ifeq ($(feature-all), 1)
+  #
+  # test-all.c passed - just set all the core feature flags to 1:
+  #
+  $(foreach feat,$(FEATURE_TESTS),$(call feature_set,$(feat)))
+  #
+  # test-all.c does not comprise these tests, so we need to
+  # for this case to get features proper values
+  #
+  $(call feature_check,compile-32)
+  $(call feature_check,compile-x32)
+  $(call feature_check,bionic)
+  $(call feature_check,libbabeltrace)
+else
+  $(foreach feat,$(FEATURE_TESTS),$(call feature_check,$(feat)))
+endif
+
+#
+# Print the result of the feature test:
+#
+feature_print_status = $(eval $(feature_print_status_code)) $(info $(MSG))
+
+define feature_print_status_code
+  ifeq ($(feature-$(1)), 1)
+    MSG = $(shell printf '...%30s: [ \033[32mon\033[m  ]' $(1))
+  else
+    MSG = $(shell printf '...%30s: [ \033[31mOFF\033[m ]' $(1))
+  endif
+endef
+
+feature_print_text = $(eval $(feature_print_text_code)) $(info $(MSG))
+define feature_print_text_code
+    MSG = $(shell printf '...%30s: %s' $(1) $(2))
+endef
+
+#
+# generates feature value assignment for name, like:
+#   $(call feature_assign,dwarf) == feature-dwarf=1
+#
+feature_assign = feature-$(1)=$(feature-$(1))
+
+FEATURE_DUMP_FILENAME = $(OUTPUT)FEATURE-DUMP$(FEATURE_USER)
+FEATURE_DUMP := $(shell touch $(FEATURE_DUMP_FILENAME); cat $(FEATURE_DUMP_FILENAME))
+
+feature_dump_check = $(eval $(feature_dump_check_code))
+define feature_dump_check_code
+  ifeq ($(findstring $(1),$(FEATURE_DUMP)),)
+    $(2) := 1
+  endif
+endef
+
+#
+# First check if any test from FEATURE_DISPLAY
+# and set feature_display := 1 if it does
+$(foreach feat,$(FEATURE_DISPLAY),$(call feature_dump_check,$(call feature_assign,$(feat)),feature_display))
+
+#
+# Now also check if any other test changed,
+# so we force FEATURE-DUMP generation
+$(foreach feat,$(FEATURE_TESTS),$(call feature_dump_check,$(call feature_assign,$(feat)),feature_dump_changed))
+
+# The $(feature_display) controls the default detection message
+# output. It's set if:
+# - detected features differes from stored features from
+#   last build (in $(FEATURE_DUMP_FILENAME) file)
+# - one of the $(FEATURE_DISPLAY) is not detected
+# - VF is enabled
+
+ifeq ($(feature_dump_changed),1)
+  $(shell rm -f $(FEATURE_DUMP_FILENAME))
+  $(foreach feat,$(FEATURE_TESTS),$(shell echo "$(call feature_assign,$(feat))" >> $(FEATURE_DUMP_FILENAME)))
+endif
+
+feature_display_check = $(eval $(feature_check_display_code))
+define feature_check_display_code
+  ifneq ($(feature-$(1)), 1)
+    feature_display := 1
+  endif
+endef
+
+$(foreach feat,$(FEATURE_DISPLAY),$(call feature_display_check,$(feat)))
+
+ifeq ($(VF),1)
+  feature_display := 1
+  feature_verbose := 1
+endif
+
+ifeq ($(feature_display),1)
+  $(info )
+  $(info Auto-detecting system features:)
+  $(foreach feat,$(FEATURE_DISPLAY),$(call feature_print_status,$(feat),))
+  ifneq ($(feature_verbose),1)
+    $(info )
+  endif
+endif
+
+ifeq ($(feature_verbose),1)
+  TMP := $(filter-out $(FEATURE_DISPLAY),$(FEATURE_TESTS))
+  $(foreach feat,$(TMP),$(call feature_print_status,$(feat),))
+  $(info )
+endif
diff --git a/tools/build/Makefile.include b/tools/build/Makefile.include
new file mode 100644
index 0000000..d360f39
--- /dev/null
+++ b/tools/build/Makefile.include
@@ -0,0 +1,9 @@
+build := -f $(srctree)/tools/build/Makefile.build dir=. obj
+
+fixdep:
+	$(Q)$(MAKE) -C $(srctree)/tools/build CFLAGS= LDFLAGS= $(OUTPUT)fixdep
+
+fixdep-clean:
+	$(Q)$(MAKE) -C $(srctree)/tools/build clean
+
+.PHONY: fixdep
diff --git a/tools/build/feature/.gitignore b/tools/build/feature/.gitignore
new file mode 100644
index 0000000..09b335b
--- /dev/null
+++ b/tools/build/feature/.gitignore
@@ -0,0 +1,3 @@
+*.d
+*.bin
+*.output
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
new file mode 100644
index 0000000..0516259
--- /dev/null
+++ b/tools/build/feature/Makefile
@@ -0,0 +1,291 @@
+# SPDX-License-Identifier: GPL-2.0
+FILES=                                          \
+         test-all.bin                           \
+         test-backtrace.bin                     \
+         test-bionic.bin                        \
+         test-dwarf.bin                         \
+         test-dwarf_getlocations.bin            \
+         test-fortify-source.bin                \
+         test-sync-compare-and-swap.bin         \
+         test-glibc.bin                         \
+         test-gtk2.bin                          \
+         test-gtk2-infobar.bin                  \
+         test-hello.bin                         \
+         test-libaudit.bin                      \
+         test-libbfd.bin                        \
+         test-disassembler-four-args.bin        \
+         test-reallocarray.bin			\
+         test-liberty.bin                       \
+         test-liberty-z.bin                     \
+         test-cplus-demangle.bin                \
+         test-libelf.bin                        \
+         test-libelf-getphdrnum.bin             \
+         test-libelf-gelf_getnote.bin           \
+         test-libelf-getshdrstrndx.bin          \
+         test-libelf-mmap.bin                   \
+         test-libnuma.bin                       \
+         test-numa_num_possible_cpus.bin        \
+         test-libperl.bin                       \
+         test-libpython.bin                     \
+         test-libpython-version.bin             \
+         test-libslang.bin                      \
+         test-libcrypto.bin                     \
+         test-libunwind.bin                     \
+         test-libunwind-debug-frame.bin         \
+         test-libunwind-x86.bin                 \
+         test-libunwind-x86_64.bin              \
+         test-libunwind-arm.bin                 \
+         test-libunwind-aarch64.bin             \
+         test-libunwind-debug-frame-arm.bin     \
+         test-libunwind-debug-frame-aarch64.bin \
+         test-pthread-attr-setaffinity-np.bin   \
+         test-pthread-barrier.bin		\
+         test-stackprotector-all.bin            \
+         test-timerfd.bin                       \
+         test-libdw-dwarf-unwind.bin            \
+         test-libbabeltrace.bin                 \
+         test-compile-32.bin                    \
+         test-compile-x32.bin                   \
+         test-zlib.bin                          \
+         test-lzma.bin                          \
+         test-bpf.bin                           \
+         test-get_cpuid.bin                     \
+         test-sdt.bin                           \
+         test-cxx.bin                           \
+         test-jvmti.bin				\
+         test-sched_getcpu.bin			\
+         test-setns.bin				\
+         test-libopencsd.bin			\
+         test-clang.bin				\
+         test-llvm.bin				\
+         test-llvm-version.bin
+
+FILES := $(addprefix $(OUTPUT),$(FILES))
+
+CC ?= $(CROSS_COMPILE)gcc
+CXX ?= $(CROSS_COMPILE)g++
+PKG_CONFIG ?= $(CROSS_COMPILE)pkg-config
+LLVM_CONFIG ?= llvm-config
+
+all: $(FILES)
+
+__BUILD = $(CC) $(CFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
+  BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1
+
+__BUILDXX = $(CXX) $(CXXFLAGS) -MD -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
+  BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
+
+###############################
+
+$(OUTPUT)test-all.bin:
+	$(BUILD) -fstack-protector-all -O2 -D_FORTIFY_SOURCE=2 -ldw -lelf -lnuma -lelf -laudit -I/usr/include/slang -lslang $(shell $(PKG_CONFIG) --libs --cflags gtk+-2.0 2>/dev/null) $(FLAGS_PERL_EMBED) $(FLAGS_PYTHON_EMBED) -DPACKAGE='"perf"' -lbfd -ldl -lz -llzma
+
+$(OUTPUT)test-hello.bin:
+	$(BUILD)
+
+$(OUTPUT)test-pthread-attr-setaffinity-np.bin:
+	$(BUILD) -D_GNU_SOURCE -lpthread
+
+$(OUTPUT)test-pthread-barrier.bin:
+	$(BUILD) -lpthread
+
+$(OUTPUT)test-stackprotector-all.bin:
+	$(BUILD) -fstack-protector-all
+
+$(OUTPUT)test-fortify-source.bin:
+	$(BUILD) -O2 -D_FORTIFY_SOURCE=2
+
+$(OUTPUT)test-bionic.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libelf.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-glibc.bin:
+	$(BUILD)
+
+$(OUTPUT)test-sched_getcpu.bin:
+	$(BUILD)
+
+$(OUTPUT)test-setns.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libopencsd.bin:
+	$(BUILD) # -lopencsd_c_api -lopencsd provided by
+		 # $(FEATURE_CHECK_LDFLAGS-libopencsd)
+
+DWARFLIBS := -ldw
+ifeq ($(findstring -static,${LDFLAGS}),-static)
+DWARFLIBS += -lelf -lebl -lz -llzma -lbz2
+endif
+
+$(OUTPUT)test-dwarf.bin:
+	$(BUILD) $(DWARFLIBS)
+
+$(OUTPUT)test-dwarf_getlocations.bin:
+	$(BUILD) $(DWARFLIBS)
+
+$(OUTPUT)test-libelf-mmap.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libelf-getphdrnum.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libelf-gelf_getnote.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libelf-getshdrstrndx.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libnuma.bin:
+	$(BUILD) -lnuma
+
+$(OUTPUT)test-numa_num_possible_cpus.bin:
+	$(BUILD) -lnuma
+
+$(OUTPUT)test-libunwind.bin:
+	$(BUILD) -lelf
+
+$(OUTPUT)test-libunwind-debug-frame.bin:
+	$(BUILD) -lelf
+$(OUTPUT)test-libunwind-x86.bin:
+	$(BUILD) -lelf -lunwind-x86
+
+$(OUTPUT)test-libunwind-x86_64.bin:
+	$(BUILD) -lelf -lunwind-x86_64
+
+$(OUTPUT)test-libunwind-arm.bin:
+	$(BUILD) -lelf -lunwind-arm
+
+$(OUTPUT)test-libunwind-aarch64.bin:
+	$(BUILD) -lelf -lunwind-aarch64
+
+$(OUTPUT)test-libunwind-debug-frame-arm.bin:
+	$(BUILD) -lelf -lunwind-arm
+
+$(OUTPUT)test-libunwind-debug-frame-aarch64.bin:
+	$(BUILD) -lelf -lunwind-aarch64
+
+$(OUTPUT)test-libaudit.bin:
+	$(BUILD) -laudit
+
+$(OUTPUT)test-libslang.bin:
+	$(BUILD) -I/usr/include/slang -lslang
+
+$(OUTPUT)test-libcrypto.bin:
+	$(BUILD) -lcrypto
+
+$(OUTPUT)test-gtk2.bin:
+	$(BUILD) $(shell $(PKG_CONFIG) --libs --cflags gtk+-2.0 2>/dev/null)
+
+$(OUTPUT)test-gtk2-infobar.bin:
+	$(BUILD) $(shell $(PKG_CONFIG) --libs --cflags gtk+-2.0 2>/dev/null)
+
+grep-libs  = $(filter -l%,$(1))
+strip-libs = $(filter-out -l%,$(1))
+
+PERL_EMBED_LDOPTS = $(shell perl -MExtUtils::Embed -e ldopts 2>/dev/null)
+PERL_EMBED_LDFLAGS = $(call strip-libs,$(PERL_EMBED_LDOPTS))
+PERL_EMBED_LIBADD = $(call grep-libs,$(PERL_EMBED_LDOPTS))
+PERL_EMBED_CCOPTS = `perl -MExtUtils::Embed -e ccopts 2>/dev/null`
+FLAGS_PERL_EMBED=$(PERL_EMBED_CCOPTS) $(PERL_EMBED_LDOPTS)
+
+$(OUTPUT)test-libperl.bin:
+	$(BUILD) $(FLAGS_PERL_EMBED)
+
+$(OUTPUT)test-libpython.bin:
+	$(BUILD) $(FLAGS_PYTHON_EMBED)
+
+$(OUTPUT)test-libpython-version.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libbfd.bin:
+	$(BUILD) -DPACKAGE='"perf"' -lbfd -lz -liberty -ldl
+
+$(OUTPUT)test-disassembler-four-args.bin:
+	$(BUILD) -DPACKAGE='"perf"' -lbfd -lopcodes
+
+$(OUTPUT)test-reallocarray.bin:
+	$(BUILD)
+
+$(OUTPUT)test-liberty.bin:
+	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty
+
+$(OUTPUT)test-liberty-z.bin:
+	$(CC) $(CFLAGS) -Wall -Werror -o $@ test-libbfd.c -DPACKAGE='"perf"' $(LDFLAGS) -lbfd -ldl -liberty -lz
+
+$(OUTPUT)test-cplus-demangle.bin:
+	$(BUILD) -liberty
+
+$(OUTPUT)test-backtrace.bin:
+	$(BUILD)
+
+$(OUTPUT)test-timerfd.bin:
+	$(BUILD)
+
+$(OUTPUT)test-libdw-dwarf-unwind.bin:
+	$(BUILD) # -ldw provided by $(FEATURE_CHECK_LDFLAGS-libdw-dwarf-unwind)
+
+$(OUTPUT)test-libbabeltrace.bin:
+	$(BUILD) # -lbabeltrace provided by $(FEATURE_CHECK_LDFLAGS-libbabeltrace)
+
+$(OUTPUT)test-sync-compare-and-swap.bin:
+	$(BUILD)
+
+$(OUTPUT)test-compile-32.bin:
+	$(CC) -m32 -o $@ test-compile.c
+
+$(OUTPUT)test-compile-x32.bin:
+	$(CC) -mx32 -o $@ test-compile.c
+
+$(OUTPUT)test-zlib.bin:
+	$(BUILD) -lz
+
+$(OUTPUT)test-lzma.bin:
+	$(BUILD) -llzma
+
+$(OUTPUT)test-get_cpuid.bin:
+	$(BUILD)
+
+$(OUTPUT)test-bpf.bin:
+	$(BUILD)
+
+$(OUTPUT)test-sdt.bin:
+	$(BUILD)
+
+$(OUTPUT)test-cxx.bin:
+	$(BUILDXX) -std=gnu++11
+
+$(OUTPUT)test-jvmti.bin:
+	$(BUILD)
+
+$(OUTPUT)test-llvm.bin:
+	$(BUILDXX) -std=gnu++11 				\
+		-I$(shell $(LLVM_CONFIG) --includedir) 		\
+		-L$(shell $(LLVM_CONFIG) --libdir)		\
+		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
+		$(shell $(LLVM_CONFIG) --system-libs)		\
+		> $(@:.bin=.make.output) 2>&1
+
+$(OUTPUT)test-llvm-version.bin:
+	$(BUILDXX) -std=gnu++11 				\
+		-I$(shell $(LLVM_CONFIG) --includedir)		\
+		> $(@:.bin=.make.output) 2>&1
+
+$(OUTPUT)test-clang.bin:
+	$(BUILDXX) -std=gnu++11 				\
+		-I$(shell $(LLVM_CONFIG) --includedir) 		\
+		-L$(shell $(LLVM_CONFIG) --libdir)		\
+		-Wl,--start-group -lclangBasic -lclangDriver	\
+		  -lclangFrontend -lclangEdit -lclangLex	\
+		  -lclangAST -Wl,--end-group 			\
+		$(shell $(LLVM_CONFIG) --libs Core option)	\
+		$(shell $(LLVM_CONFIG) --system-libs)		\
+		> $(@:.bin=.make.output) 2>&1
+
+-include $(OUTPUT)*.d
+
+###############################
+
+clean:
+	rm -f $(FILES) $(OUTPUT)*.d $(FILES:.bin=.make.output)
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
new file mode 100644
index 0000000..8dc20a6
--- /dev/null
+++ b/tools/build/feature/test-all.c
@@ -0,0 +1,209 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * test-all.c: Try to build all the main testcases at once.
+ *
+ * A well-configured system will have all the prereqs installed, so we can speed
+ * up auto-detection on such systems.
+ */
+
+/*
+ * Quirk: Python and Perl headers cannot be in arbitrary places, so keep
+ * these 3 testcases at the top:
+ */
+#define main main_test_libpython
+# include "test-libpython.c"
+#undef main
+
+#define main main_test_libpython_version
+# include "test-libpython-version.c"
+#undef main
+
+#define main main_test_libperl
+# include "test-libperl.c"
+#undef main
+
+#define main main_test_hello
+# include "test-hello.c"
+#undef main
+
+#define main main_test_libelf
+# include "test-libelf.c"
+#undef main
+
+#define main main_test_libelf_mmap
+# include "test-libelf-mmap.c"
+#undef main
+
+#define main main_test_glibc
+# include "test-glibc.c"
+#undef main
+
+#define main main_test_dwarf
+# include "test-dwarf.c"
+#undef main
+
+#define main main_test_dwarf_getlocations
+# include "test-dwarf_getlocations.c"
+#undef main
+
+#define main main_test_libelf_getphdrnum
+# include "test-libelf-getphdrnum.c"
+#undef main
+
+#define main main_test_libelf_gelf_getnote
+# include "test-libelf-gelf_getnote.c"
+#undef main
+
+#define main main_test_libelf_getshdrstrndx
+# include "test-libelf-getshdrstrndx.c"
+#undef main
+
+#define main main_test_libunwind
+# include "test-libunwind.c"
+#undef main
+
+#define main main_test_libaudit
+# include "test-libaudit.c"
+#undef main
+
+#define main main_test_libslang
+# include "test-libslang.c"
+#undef main
+
+#define main main_test_gtk2
+# include "test-gtk2.c"
+#undef main
+
+#define main main_test_gtk2_infobar
+# include "test-gtk2-infobar.c"
+#undef main
+
+#define main main_test_libbfd
+# include "test-libbfd.c"
+#undef main
+
+#define main main_test_backtrace
+# include "test-backtrace.c"
+#undef main
+
+#define main main_test_libnuma
+# include "test-libnuma.c"
+#undef main
+
+#define main main_test_numa_num_possible_cpus
+# include "test-numa_num_possible_cpus.c"
+#undef main
+
+#define main main_test_timerfd
+# include "test-timerfd.c"
+#undef main
+
+#define main main_test_stackprotector_all
+# include "test-stackprotector-all.c"
+#undef main
+
+#define main main_test_libdw_dwarf_unwind
+# include "test-libdw-dwarf-unwind.c"
+#undef main
+
+#define main main_test_sync_compare_and_swap
+# include "test-sync-compare-and-swap.c"
+#undef main
+
+#define main main_test_zlib
+# include "test-zlib.c"
+#undef main
+
+#define main main_test_pthread_attr_setaffinity_np
+# include "test-pthread-attr-setaffinity-np.c"
+#undef main
+
+#define main main_test_pthread_barrier
+# include "test-pthread-barrier.c"
+#undef main
+
+#define main main_test_sched_getcpu
+# include "test-sched_getcpu.c"
+#undef main
+
+# if 0
+/*
+ * Disable libbabeltrace check for test-all, because the requested
+ * library version is not released yet in most distributions. Will
+ * reenable later.
+ */
+
+#define main main_test_libbabeltrace
+# include "test-libbabeltrace.c"
+#undef main
+#endif
+
+#define main main_test_lzma
+# include "test-lzma.c"
+#undef main
+
+#define main main_test_get_cpuid
+# include "test-get_cpuid.c"
+#undef main
+
+#define main main_test_bpf
+# include "test-bpf.c"
+#undef main
+
+#define main main_test_libcrypto
+# include "test-libcrypto.c"
+#undef main
+
+#define main main_test_sdt
+# include "test-sdt.c"
+#undef main
+
+#define main main_test_setns
+# include "test-setns.c"
+#undef main
+
+#define main main_test_libopencsd
+# include "test-libopencsd.c"
+#undef main
+
+int main(int argc, char *argv[])
+{
+	main_test_libpython();
+	main_test_libpython_version();
+	main_test_libperl();
+	main_test_hello();
+	main_test_libelf();
+	main_test_libelf_mmap();
+	main_test_glibc();
+	main_test_dwarf();
+	main_test_dwarf_getlocations();
+	main_test_libelf_getphdrnum();
+	main_test_libelf_gelf_getnote();
+	main_test_libelf_getshdrstrndx();
+	main_test_libunwind();
+	main_test_libaudit();
+	main_test_libslang();
+	main_test_gtk2(argc, argv);
+	main_test_gtk2_infobar(argc, argv);
+	main_test_libbfd();
+	main_test_backtrace();
+	main_test_libnuma();
+	main_test_numa_num_possible_cpus();
+	main_test_timerfd();
+	main_test_stackprotector_all();
+	main_test_libdw_dwarf_unwind();
+	main_test_sync_compare_and_swap(argc, argv);
+	main_test_zlib();
+	main_test_pthread_attr_setaffinity_np();
+	main_test_pthread_barrier();
+	main_test_lzma();
+	main_test_get_cpuid();
+	main_test_bpf();
+	main_test_libcrypto();
+	main_test_sched_getcpu();
+	main_test_sdt();
+	main_test_setns();
+	main_test_libopencsd();
+
+	return 0;
+}
diff --git a/tools/build/feature/test-backtrace.c b/tools/build/feature/test-backtrace.c
new file mode 100644
index 0000000..e9ddd27
--- /dev/null
+++ b/tools/build/feature/test-backtrace.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <execinfo.h>
+#include <stdio.h>
+
+int main(void)
+{
+	void *backtrace_fns[10];
+	size_t entries;
+
+	entries = backtrace(backtrace_fns, 10);
+	backtrace_symbols_fd(backtrace_fns, entries, 1);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-bionic.c b/tools/build/feature/test-bionic.c
new file mode 100644
index 0000000..4bcc977
--- /dev/null
+++ b/tools/build/feature/test-bionic.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <android/api-level.h>
+
+int main(void)
+{
+	return __ANDROID_API__;
+}
diff --git a/tools/build/feature/test-bpf.c b/tools/build/feature/test-bpf.c
new file mode 100644
index 0000000..82070ea
--- /dev/null
+++ b/tools/build/feature/test-bpf.c
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <asm/unistd.h>
+#include <linux/bpf.h>
+#include <unistd.h>
+
+#ifndef __NR_bpf
+# if defined(__i386__)
+#  define __NR_bpf 357
+# elif defined(__x86_64__)
+#  define __NR_bpf 321
+# elif defined(__aarch64__)
+#  define __NR_bpf 280
+# elif defined(__sparc__)
+#  define __NR_bpf 349
+# elif defined(__s390__)
+#  define __NR_bpf 351
+# else
+#  error __NR_bpf not defined. libbpf does not support your arch.
+# endif
+#endif
+
+int main(void)
+{
+	union bpf_attr attr;
+
+	/* Check fields in attr */
+	attr.prog_type = BPF_PROG_TYPE_KPROBE;
+	attr.insn_cnt = 0;
+	attr.insns = 0;
+	attr.license = 0;
+	attr.log_buf = 0;
+	attr.log_size = 0;
+	attr.log_level = 0;
+	attr.kern_version = 0;
+	attr.prog_flags = 0;
+
+	/*
+	 * Test existence of __NR_bpf and BPF_PROG_LOAD.
+	 * This call should fail if we run the testcase.
+	 */
+	return syscall(__NR_bpf, BPF_PROG_LOAD, &attr, sizeof(attr));
+}
diff --git a/tools/build/feature/test-clang.cpp b/tools/build/feature/test-clang.cpp
new file mode 100644
index 0000000..a2b3f09
--- /dev/null
+++ b/tools/build/feature/test-clang.cpp
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "clang/Basic/VirtualFileSystem.h"
+#include "clang/Driver/Driver.h"
+#include "clang/Frontend/TextDiagnosticPrinter.h"
+#include "llvm/ADT/IntrusiveRefCntPtr.h"
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace clang::driver;
+
+int main()
+{
+	IntrusiveRefCntPtr<DiagnosticIDs> DiagID(new DiagnosticIDs());
+	IntrusiveRefCntPtr<DiagnosticOptions> DiagOpts = new DiagnosticOptions();
+
+	DiagnosticsEngine Diags(DiagID, &*DiagOpts);
+	Driver TheDriver("test", "bpf-pc-linux", Diags);
+
+	llvm::llvm_shutdown();
+	return 0;
+}
diff --git a/tools/build/feature/test-compile.c b/tools/build/feature/test-compile.c
new file mode 100644
index 0000000..9821b82
--- /dev/null
+++ b/tools/build/feature/test-compile.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+int main(void)
+{
+	printf("Hello World!\n");
+	return 0;
+}
diff --git a/tools/build/feature/test-cplus-demangle.c b/tools/build/feature/test-cplus-demangle.c
new file mode 100644
index 0000000..2ba5647
--- /dev/null
+++ b/tools/build/feature/test-cplus-demangle.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+extern int printf(const char *format, ...);
+extern char *cplus_demangle(const char *, int);
+
+int main(void)
+{
+	char symbol[4096] = "FieldName__9ClassNameFd";
+	char *tmp;
+
+	tmp = cplus_demangle(symbol, 0);
+
+	printf("demangled symbol: {%s}\n", tmp);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-cxx.cpp b/tools/build/feature/test-cxx.cpp
new file mode 100644
index 0000000..396aaed
--- /dev/null
+++ b/tools/build/feature/test-cxx.cpp
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <iostream>
+#include <memory>
+
+static void print_str(std::string s)
+{
+	std::cout << s << std::endl;
+}
+
+int main()
+{
+	std::string s("Hello World!");
+	print_str(std::move(s));
+	std::cout << "|" << s << "|" << std::endl;
+	return 0;
+}
diff --git a/tools/build/feature/test-disassembler-four-args.c b/tools/build/feature/test-disassembler-four-args.c
new file mode 100644
index 0000000..45ce65c
--- /dev/null
+++ b/tools/build/feature/test-disassembler-four-args.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <bfd.h>
+#include <dis-asm.h>
+
+int main(void)
+{
+	bfd *abfd = bfd_openr(NULL, NULL);
+
+	disassembler(bfd_get_arch(abfd),
+		     bfd_big_endian(abfd),
+		     bfd_get_mach(abfd),
+		     abfd);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-dwarf.c b/tools/build/feature/test-dwarf.c
new file mode 100644
index 0000000..8d474bd
--- /dev/null
+++ b/tools/build/feature/test-dwarf.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <dwarf.h>
+#include <elfutils/libdw.h>
+#include <elfutils/version.h>
+
+int main(void)
+{
+	Dwarf *dbg = dwarf_begin(0, DWARF_C_READ);
+
+	return (long)dbg;
+}
diff --git a/tools/build/feature/test-dwarf_getlocations.c b/tools/build/feature/test-dwarf_getlocations.c
new file mode 100644
index 0000000..78fb4a1
--- /dev/null
+++ b/tools/build/feature/test-dwarf_getlocations.c
@@ -0,0 +1,13 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdlib.h>
+#include <elfutils/libdw.h>
+
+int main(void)
+{
+	Dwarf_Addr base, start, end;
+	Dwarf_Attribute attr;
+	Dwarf_Op *op;
+        size_t nops;
+	ptrdiff_t offset = 0;
+        return (int)dwarf_getlocations(&attr, offset, &base, &start, &end, &op, &nops);
+}
diff --git a/tools/build/feature/test-fortify-source.c b/tools/build/feature/test-fortify-source.c
new file mode 100644
index 0000000..c9f398d
--- /dev/null
+++ b/tools/build/feature/test-fortify-source.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main(void)
+{
+	return puts("hi");
+}
diff --git a/tools/build/feature/test-get_cpuid.c b/tools/build/feature/test-get_cpuid.c
new file mode 100644
index 0000000..bb4f065
--- /dev/null
+++ b/tools/build/feature/test-get_cpuid.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <cpuid.h>
+
+int main(void)
+{
+	unsigned int eax = 0, ebx = 0, ecx = 0, edx = 0;
+	return __get_cpuid(0x15, &eax, &ebx, &ecx, &edx);
+}
diff --git a/tools/build/feature/test-glibc.c b/tools/build/feature/test-glibc.c
new file mode 100644
index 0000000..9ab8e90
--- /dev/null
+++ b/tools/build/feature/test-glibc.c
@@ -0,0 +1,20 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdlib.h>
+
+#if !defined(__UCLIBC__)
+#include <gnu/libc-version.h>
+#else
+#define XSTR(s) STR(s)
+#define STR(s) #s
+#endif
+
+int main(void)
+{
+#if !defined(__UCLIBC__)
+	const char *version = gnu_get_libc_version();
+#else
+	const char *version = XSTR(__GLIBC__) "." XSTR(__GLIBC_MINOR__);
+#endif
+
+	return (long)version;
+}
diff --git a/tools/build/feature/test-gtk2-infobar.c b/tools/build/feature/test-gtk2-infobar.c
new file mode 100644
index 0000000..b1b716d
--- /dev/null
+++ b/tools/build/feature/test-gtk2-infobar.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+#pragma GCC diagnostic ignored "-Wstrict-prototypes"
+#include <gtk/gtk.h>
+#pragma GCC diagnostic error "-Wstrict-prototypes"
+
+int main(int argc, char *argv[])
+{
+	gtk_init(&argc, &argv);
+	gtk_info_bar_new();
+
+	return 0;
+}
diff --git a/tools/build/feature/test-gtk2.c b/tools/build/feature/test-gtk2.c
new file mode 100644
index 0000000..2aaf4bf
--- /dev/null
+++ b/tools/build/feature/test-gtk2.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#pragma GCC diagnostic ignored "-Wstrict-prototypes"
+#include <gtk/gtk.h>
+#pragma GCC diagnostic error "-Wstrict-prototypes"
+
+int main(int argc, char *argv[])
+{
+	gtk_init(&argc, &argv);
+
+        return 0;
+}
diff --git a/tools/build/feature/test-hello.c b/tools/build/feature/test-hello.c
new file mode 100644
index 0000000..c9f398d
--- /dev/null
+++ b/tools/build/feature/test-hello.c
@@ -0,0 +1,6 @@
+#include <stdio.h>
+
+int main(void)
+{
+	return puts("hi");
+}
diff --git a/tools/build/feature/test-jvmti.c b/tools/build/feature/test-jvmti.c
new file mode 100644
index 0000000..5cf3119
--- /dev/null
+++ b/tools/build/feature/test-jvmti.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <jvmti.h>
+#include <jvmticmlr.h>
+
+int main(void)
+{
+	JavaVM			jvm	__attribute__((unused));
+	jvmtiEventCallbacks	cb	__attribute__((unused));
+	jvmtiCapabilities	caps	__attribute__((unused));
+	jvmtiJlocationFormat	format	__attribute__((unused));
+	jvmtiEnv		jvmti	__attribute__((unused));
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libaudit.c b/tools/build/feature/test-libaudit.c
new file mode 100644
index 0000000..f5b0863
--- /dev/null
+++ b/tools/build/feature/test-libaudit.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libaudit.h>
+
+extern int printf(const char *format, ...);
+
+int main(void)
+{
+	printf("error message: %s\n", audit_errno_to_name(0));
+
+	return audit_open();
+}
diff --git a/tools/build/feature/test-libbabeltrace.c b/tools/build/feature/test-libbabeltrace.c
new file mode 100644
index 0000000..10bb69d
--- /dev/null
+++ b/tools/build/feature/test-libbabeltrace.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <babeltrace/ctf-writer/writer.h>
+#include <babeltrace/ctf-ir/stream-class.h>
+
+int main(void)
+{
+	bt_ctf_stream_class_get_packet_context_type((void *) 0);
+	return 0;
+}
diff --git a/tools/build/feature/test-libbfd.c b/tools/build/feature/test-libbfd.c
new file mode 100644
index 0000000..afa46b0
--- /dev/null
+++ b/tools/build/feature/test-libbfd.c
@@ -0,0 +1,16 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <bfd.h>
+
+extern int printf(const char *format, ...);
+
+int main(void)
+{
+	char symbol[4096] = "FieldName__9ClassNameFd";
+	char *tmp;
+
+	tmp = bfd_demangle(0, symbol, 0);
+
+	printf("demangled symbol: {%s}\n", tmp);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libcrypto.c b/tools/build/feature/test-libcrypto.c
new file mode 100644
index 0000000..a98174e
--- /dev/null
+++ b/tools/build/feature/test-libcrypto.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <openssl/sha.h>
+#include <openssl/md5.h>
+
+int main(void)
+{
+	MD5_CTX context;
+	unsigned char md[MD5_DIGEST_LENGTH + SHA_DIGEST_LENGTH];
+	unsigned char dat[] = "12345";
+
+	MD5_Init(&context);
+	MD5_Update(&context, &dat[0], sizeof(dat));
+	MD5_Final(&md[0], &context);
+
+	SHA1(&dat[0], sizeof(dat), &md[0]);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libdw-dwarf-unwind.c b/tools/build/feature/test-libdw-dwarf-unwind.c
new file mode 100644
index 0000000..ed03d95
--- /dev/null
+++ b/tools/build/feature/test-libdw-dwarf-unwind.c
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <elfutils/libdwfl.h>
+
+int main(void)
+{
+	/*
+	 * This function is guarded via: __nonnull_attribute__ (1, 2).
+	 * Passing '1' as arguments value. This code is never executed,
+	 * only compiled.
+	 */
+	dwfl_thread_getframes((void *) 1, (void *) 1, NULL);
+	return 0;
+}
diff --git a/tools/build/feature/test-libelf-gelf_getnote.c b/tools/build/feature/test-libelf-gelf_getnote.c
new file mode 100644
index 0000000..075d062
--- /dev/null
+++ b/tools/build/feature/test-libelf-gelf_getnote.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdlib.h>
+#include <gelf.h>
+
+int main(void)
+{
+	return gelf_getnote(NULL, 0, NULL, NULL, NULL);
+}
diff --git a/tools/build/feature/test-libelf-getphdrnum.c b/tools/build/feature/test-libelf-getphdrnum.c
new file mode 100644
index 0000000..96a7f8d
--- /dev/null
+++ b/tools/build/feature/test-libelf-getphdrnum.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libelf.h>
+
+int main(void)
+{
+	size_t dst;
+
+	return elf_getphdrnum(0, &dst);
+}
diff --git a/tools/build/feature/test-libelf-getshdrstrndx.c b/tools/build/feature/test-libelf-getshdrstrndx.c
new file mode 100644
index 0000000..ae9f2ff
--- /dev/null
+++ b/tools/build/feature/test-libelf-getshdrstrndx.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libelf.h>
+
+int main(void)
+{
+	size_t dst;
+
+	return elf_getshdrstrndx(0, &dst);
+}
diff --git a/tools/build/feature/test-libelf-mmap.c b/tools/build/feature/test-libelf-mmap.c
new file mode 100644
index 0000000..2c3ef81
--- /dev/null
+++ b/tools/build/feature/test-libelf-mmap.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libelf.h>
+
+int main(void)
+{
+	Elf *elf = elf_begin(0, ELF_C_READ_MMAP, 0);
+
+	return (long)elf;
+}
diff --git a/tools/build/feature/test-libelf.c b/tools/build/feature/test-libelf.c
new file mode 100644
index 0000000..9050441
--- /dev/null
+++ b/tools/build/feature/test-libelf.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libelf.h>
+
+int main(void)
+{
+	Elf *elf = elf_begin(0, ELF_C_READ, 0);
+
+	return (long)elf;
+}
diff --git a/tools/build/feature/test-libnuma.c b/tools/build/feature/test-libnuma.c
new file mode 100644
index 0000000..b3aa59f
--- /dev/null
+++ b/tools/build/feature/test-libnuma.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <numa.h>
+#include <numaif.h>
+
+int main(void)
+{
+	numa_available();
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libopencsd.c b/tools/build/feature/test-libopencsd.c
new file mode 100644
index 0000000..5ff1246
--- /dev/null
+++ b/tools/build/feature/test-libopencsd.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <opencsd/c_api/opencsd_c_api.h>
+
+int main(void)
+{
+	(void)ocsd_get_version();
+	return 0;
+}
diff --git a/tools/build/feature/test-libperl.c b/tools/build/feature/test-libperl.c
new file mode 100644
index 0000000..0415f43
--- /dev/null
+++ b/tools/build/feature/test-libperl.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <EXTERN.h>
+#include <perl.h>
+
+int main(void)
+{
+	perl_alloc();
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libpython-version.c b/tools/build/feature/test-libpython-version.c
new file mode 100644
index 0000000..47714b9
--- /dev/null
+++ b/tools/build/feature/test-libpython-version.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <Python.h>
+
+#if PY_VERSION_HEX >= 0x03000000
+	#error
+#endif
+
+int main(void)
+{
+	return 0;
+}
diff --git a/tools/build/feature/test-libpython.c b/tools/build/feature/test-libpython.c
new file mode 100644
index 0000000..0c1641b
--- /dev/null
+++ b/tools/build/feature/test-libpython.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <Python.h>
+
+int main(void)
+{
+	Py_Initialize();
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libslang.c b/tools/build/feature/test-libslang.c
new file mode 100644
index 0000000..9cbff8d
--- /dev/null
+++ b/tools/build/feature/test-libslang.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <slang.h>
+
+int main(void)
+{
+	return SLsmg_init_smg();
+}
diff --git a/tools/build/feature/test-libunwind-aarch64.c b/tools/build/feature/test-libunwind-aarch64.c
new file mode 100644
index 0000000..323803f
--- /dev/null
+++ b/tools/build/feature/test-libunwind-aarch64.c
@@ -0,0 +1,27 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind-aarch64.h>
+#include <stdlib.h>
+
+extern int UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
+					       unw_word_t ip,
+					       unw_dyn_info_t *di,
+					       unw_proc_info_t *pi,
+					       int need_unwind_info, void *arg);
+
+#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
+
+static unw_accessors_t accessors;
+
+int main(void)
+{
+	unw_addr_space_t addr_space;
+
+	addr_space = unw_create_addr_space(&accessors, 0);
+	if (addr_space)
+		return 0;
+
+	unw_init_remote(NULL, addr_space, NULL);
+	dwarf_search_unwind_table(addr_space, 0, NULL, NULL, 0, NULL);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libunwind-arm.c b/tools/build/feature/test-libunwind-arm.c
new file mode 100644
index 0000000..cb378b7
--- /dev/null
+++ b/tools/build/feature/test-libunwind-arm.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind-arm.h>
+#include <stdlib.h>
+
+extern int UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
+					       unw_word_t ip,
+					       unw_dyn_info_t *di,
+					       unw_proc_info_t *pi,
+					       int need_unwind_info, void *arg);
+
+
+#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
+
+static unw_accessors_t accessors;
+
+int main(void)
+{
+	unw_addr_space_t addr_space;
+
+	addr_space = unw_create_addr_space(&accessors, 0);
+	if (addr_space)
+		return 0;
+
+	unw_init_remote(NULL, addr_space, NULL);
+	dwarf_search_unwind_table(addr_space, 0, NULL, NULL, 0, NULL);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libunwind-debug-frame-aarch64.c b/tools/build/feature/test-libunwind-debug-frame-aarch64.c
new file mode 100644
index 0000000..36d6646
--- /dev/null
+++ b/tools/build/feature/test-libunwind-debug-frame-aarch64.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind-aarch64.h>
+#include <stdlib.h>
+
+extern int
+UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug,
+				 unw_word_t ip, unw_word_t segbase,
+				 const char *obj_name, unw_word_t start,
+				 unw_word_t end);
+
+#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame)
+
+int main(void)
+{
+	dwarf_find_debug_frame(0, NULL, 0, 0, NULL, 0, 0);
+	return 0;
+}
diff --git a/tools/build/feature/test-libunwind-debug-frame-arm.c b/tools/build/feature/test-libunwind-debug-frame-arm.c
new file mode 100644
index 0000000..8696e48
--- /dev/null
+++ b/tools/build/feature/test-libunwind-debug-frame-arm.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind-arm.h>
+#include <stdlib.h>
+
+extern int
+UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug,
+				 unw_word_t ip, unw_word_t segbase,
+				 const char *obj_name, unw_word_t start,
+				 unw_word_t end);
+
+#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame)
+
+int main(void)
+{
+	dwarf_find_debug_frame(0, NULL, 0, 0, NULL, 0, 0);
+	return 0;
+}
diff --git a/tools/build/feature/test-libunwind-debug-frame.c b/tools/build/feature/test-libunwind-debug-frame.c
new file mode 100644
index 0000000..efb55cd
--- /dev/null
+++ b/tools/build/feature/test-libunwind-debug-frame.c
@@ -0,0 +1,17 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind.h>
+#include <stdlib.h>
+
+extern int
+UNW_OBJ(dwarf_find_debug_frame) (int found, unw_dyn_info_t *di_debug,
+				 unw_word_t ip, unw_word_t segbase,
+				 const char *obj_name, unw_word_t start,
+				 unw_word_t end);
+
+#define dwarf_find_debug_frame UNW_OBJ(dwarf_find_debug_frame)
+
+int main(void)
+{
+	dwarf_find_debug_frame(0, NULL, 0, 0, NULL, 0, 0);
+	return 0;
+}
diff --git a/tools/build/feature/test-libunwind-x86.c b/tools/build/feature/test-libunwind-x86.c
new file mode 100644
index 0000000..e5e0f6c
--- /dev/null
+++ b/tools/build/feature/test-libunwind-x86.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind-x86.h>
+#include <stdlib.h>
+
+extern int UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
+					       unw_word_t ip,
+					       unw_dyn_info_t *di,
+					       unw_proc_info_t *pi,
+					       int need_unwind_info, void *arg);
+
+
+#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
+
+static unw_accessors_t accessors;
+
+int main(void)
+{
+	unw_addr_space_t addr_space;
+
+	addr_space = unw_create_addr_space(&accessors, 0);
+	if (addr_space)
+		return 0;
+
+	unw_init_remote(NULL, addr_space, NULL);
+	dwarf_search_unwind_table(addr_space, 0, NULL, NULL, 0, NULL);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libunwind-x86_64.c b/tools/build/feature/test-libunwind-x86_64.c
new file mode 100644
index 0000000..62ae4db
--- /dev/null
+++ b/tools/build/feature/test-libunwind-x86_64.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind-x86_64.h>
+#include <stdlib.h>
+
+extern int UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
+					       unw_word_t ip,
+					       unw_dyn_info_t *di,
+					       unw_proc_info_t *pi,
+					       int need_unwind_info, void *arg);
+
+
+#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
+
+static unw_accessors_t accessors;
+
+int main(void)
+{
+	unw_addr_space_t addr_space;
+
+	addr_space = unw_create_addr_space(&accessors, 0);
+	if (addr_space)
+		return 0;
+
+	unw_init_remote(NULL, addr_space, NULL);
+	dwarf_search_unwind_table(addr_space, 0, NULL, NULL, 0, NULL);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-libunwind.c b/tools/build/feature/test-libunwind.c
new file mode 100644
index 0000000..53fd266
--- /dev/null
+++ b/tools/build/feature/test-libunwind.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <libunwind.h>
+#include <stdlib.h>
+
+extern int UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
+                                      unw_word_t ip,
+                                      unw_dyn_info_t *di,
+                                      unw_proc_info_t *pi,
+                                      int need_unwind_info, void *arg);
+
+
+#define dwarf_search_unwind_table UNW_OBJ(dwarf_search_unwind_table)
+
+static unw_accessors_t accessors;
+
+int main(void)
+{
+	unw_addr_space_t addr_space;
+
+	addr_space = unw_create_addr_space(&accessors, 0);
+	if (addr_space)
+		return 0;
+
+	unw_init_remote(NULL, addr_space, NULL);
+	dwarf_search_unwind_table(addr_space, 0, NULL, NULL, 0, NULL);
+
+	return 0;
+}
diff --git a/tools/build/feature/test-llvm-version.cpp b/tools/build/feature/test-llvm-version.cpp
new file mode 100644
index 0000000..8a09162
--- /dev/null
+++ b/tools/build/feature/test-llvm-version.cpp
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <cstdio>
+#include "llvm/Config/llvm-config.h"
+
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+#define pass int main() {printf("%x\n", NUM_VERSION); return 0;}
+
+#if NUM_VERSION >= 0x030900
+pass
+#else
+# error This LLVM is not tested yet.
+#endif
diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
new file mode 100644
index 0000000..88a3d1b
--- /dev/null
+++ b/tools/build/feature/test-llvm.cpp
@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/raw_ostream.h"
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+
+#if NUM_VERSION < 0x030900
+# error "LLVM version too low"
+#endif
+int main()
+{
+	llvm::errs() << "Hello World!\n";
+	llvm::llvm_shutdown();
+	return 0;
+}
diff --git a/tools/build/feature/test-lzma.c b/tools/build/feature/test-lzma.c
new file mode 100644
index 0000000..78682bb
--- /dev/null
+++ b/tools/build/feature/test-lzma.c
@@ -0,0 +1,11 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <lzma.h>
+
+int main(void)
+{
+	lzma_stream strm = LZMA_STREAM_INIT;
+	int ret;
+
+	ret = lzma_stream_decoder(&strm, UINT64_MAX, LZMA_CONCATENATED);
+	return ret ? -1 : 0;
+}
diff --git a/tools/build/feature/test-numa_num_possible_cpus.c b/tools/build/feature/test-numa_num_possible_cpus.c
new file mode 100644
index 0000000..573d07b
--- /dev/null
+++ b/tools/build/feature/test-numa_num_possible_cpus.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <numa.h>
+
+int main(void)
+{
+	return numa_num_possible_cpus();
+}
diff --git a/tools/build/feature/test-pthread-attr-setaffinity-np.c b/tools/build/feature/test-pthread-attr-setaffinity-np.c
new file mode 100644
index 0000000..38c7113
--- /dev/null
+++ b/tools/build/feature/test-pthread-attr-setaffinity-np.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdint.h>
+#include <pthread.h>
+#include <sched.h>
+
+int main(void)
+{
+	int ret = 0;
+	pthread_attr_t thread_attr;
+	cpu_set_t cs;
+
+	pthread_attr_init(&thread_attr);
+	CPU_ZERO(&cs);
+
+	ret = pthread_attr_setaffinity_np(&thread_attr, sizeof(cs), &cs);
+
+	return ret;
+}
diff --git a/tools/build/feature/test-pthread-barrier.c b/tools/build/feature/test-pthread-barrier.c
new file mode 100644
index 0000000..0558d93
--- /dev/null
+++ b/tools/build/feature/test-pthread-barrier.c
@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdint.h>
+#include <pthread.h>
+
+int main(void)
+{
+	pthread_barrier_t barrier;
+
+	pthread_barrier_init(&barrier, NULL, 1);
+	pthread_barrier_wait(&barrier);
+	return pthread_barrier_destroy(&barrier);
+}
diff --git a/tools/build/feature/test-reallocarray.c b/tools/build/feature/test-reallocarray.c
new file mode 100644
index 0000000..8170de3
--- /dev/null
+++ b/tools/build/feature/test-reallocarray.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#define _GNU_SOURCE
+#include <stdlib.h>
+
+int main(void)
+{
+	return !!reallocarray(NULL, 1, 1);
+}
diff --git a/tools/build/feature/test-sched_getcpu.c b/tools/build/feature/test-sched_getcpu.c
new file mode 100644
index 0000000..e448deb
--- /dev/null
+++ b/tools/build/feature/test-sched_getcpu.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+#include <sched.h>
+
+int main(void)
+{
+	return sched_getcpu();
+}
diff --git a/tools/build/feature/test-sdt.c b/tools/build/feature/test-sdt.c
new file mode 100644
index 0000000..22737b0
--- /dev/null
+++ b/tools/build/feature/test-sdt.c
@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <sys/sdt.h>
+
+int main(void)
+{
+	DTRACE_PROBE(provider, name);
+	return 0;
+}
diff --git a/tools/build/feature/test-setns.c b/tools/build/feature/test-setns.c
new file mode 100644
index 0000000..1f714d2
--- /dev/null
+++ b/tools/build/feature/test-setns.c
@@ -0,0 +1,7 @@
+#define _GNU_SOURCE
+#include <sched.h>
+
+int main(void)
+{
+	return setns(0, 0);
+}
diff --git a/tools/build/feature/test-stackprotector-all.c b/tools/build/feature/test-stackprotector-all.c
new file mode 100644
index 0000000..c8a5719
--- /dev/null
+++ b/tools/build/feature/test-stackprotector-all.c
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdio.h>
+
+int main(void)
+{
+	return puts("hi");
+}
diff --git a/tools/build/feature/test-sync-compare-and-swap.c b/tools/build/feature/test-sync-compare-and-swap.c
new file mode 100644
index 0000000..1e38d19
--- /dev/null
+++ b/tools/build/feature/test-sync-compare-and-swap.c
@@ -0,0 +1,15 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <stdint.h>
+
+volatile uint64_t x;
+
+int main(int argc, char *argv[])
+{
+	uint64_t old, new = argc;
+
+	argv = argv;
+	do {
+		old = __sync_val_compare_and_swap(&x, 0, 0);
+	} while (!__sync_bool_compare_and_swap(&x, old, new));
+	return old == new;
+}
diff --git a/tools/build/feature/test-timerfd.c b/tools/build/feature/test-timerfd.c
new file mode 100644
index 0000000..9c72c69
--- /dev/null
+++ b/tools/build/feature/test-timerfd.c
@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * test for timerfd functions used by perf-kvm-stat-live
+ */
+#include <sys/timerfd.h>
+
+int main(void)
+{
+	struct itimerspec new_value;
+
+	int fd = timerfd_create(CLOCK_MONOTONIC, TFD_NONBLOCK);
+	if (fd < 0)
+		return 1;
+
+	if (timerfd_settime(fd, 0, &new_value, NULL) != 0)
+		return 1;
+
+	return 0;
+}
diff --git a/tools/build/feature/test-zlib.c b/tools/build/feature/test-zlib.c
new file mode 100644
index 0000000..da6c357
--- /dev/null
+++ b/tools/build/feature/test-zlib.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <zlib.h>
+
+int main(void)
+{
+	z_stream zs;
+
+	inflateInit(&zs);
+	return 0;
+}
diff --git a/tools/build/fixdep.c b/tools/build/fixdep.c
new file mode 100644
index 0000000..2501fea
--- /dev/null
+++ b/tools/build/fixdep.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * "Optimize" a list of dependencies as spit out by gcc -MD
+ * for the build framework.
+ *
+ * Original author:
+ *   Copyright    2002 by Kai Germaschewski  <kai.germaschewski@gmx.de>
+ *
+ * This code has been borrowed from kbuild's fixdep (scripts/basic/fixdep.c),
+ * Please check it for detailed explanation. This fixdep borow only the
+ * base transformation of dependecies without the CONFIG mangle.
+ */
+
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <sys/mman.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <limits.h>
+
+char *target;
+char *depfile;
+char *cmdline;
+
+static void usage(void)
+{
+	fprintf(stderr, "Usage: fixdep <depfile> <target> <cmdline>\n");
+	exit(1);
+}
+
+/*
+ * Print out the commandline prefixed with cmd_<target filename> :=
+ */
+static void print_cmdline(void)
+{
+	printf("cmd_%s := %s\n\n", target, cmdline);
+}
+
+/*
+ * Important: The below generated source_foo.o and deps_foo.o variable
+ * assignments are parsed not only by make, but also by the rather simple
+ * parser in scripts/mod/sumversion.c.
+ */
+static void parse_dep_file(void *map, size_t len)
+{
+	char *m = map;
+	char *end = m + len;
+	char *p;
+	char s[PATH_MAX];
+	int is_target, has_target = 0;
+	int saw_any_target = 0;
+	int is_first_dep = 0;
+
+	while (m < end) {
+		/* Skip any "white space" */
+		while (m < end && (*m == ' ' || *m == '\\' || *m == '\n'))
+			m++;
+		/* Find next "white space" */
+		p = m;
+		while (p < end && *p != ' ' && *p != '\\' && *p != '\n')
+			p++;
+		/* Is the token we found a target name? */
+		is_target = (*(p-1) == ':');
+		/* Don't write any target names into the dependency file */
+		if (is_target) {
+			/* The /next/ file is the first dependency */
+			is_first_dep = 1;
+			has_target = 1;
+		} else if (has_target) {
+			/* Save this token/filename */
+			memcpy(s, m, p-m);
+			s[p - m] = 0;
+
+			/*
+			 * Do not list the source file as dependency,
+			 * so that kbuild is not confused if a .c file
+			 * is rewritten into .S or vice versa. Storing
+			 * it in source_* is needed for modpost to
+			 * compute srcversions.
+			 */
+			if (is_first_dep) {
+				/*
+				 * If processing the concatenation of
+				 * multiple dependency files, only
+				 * process the first target name, which
+				 * will be the original source name,
+				 * and ignore any other target names,
+				 * which will be intermediate temporary
+				 * files.
+				 */
+				if (!saw_any_target) {
+					saw_any_target = 1;
+					printf("source_%s := %s\n\n",
+						target, s);
+					printf("deps_%s := \\\n",
+						target);
+				}
+				is_first_dep = 0;
+			} else
+				printf("  %s \\\n", s);
+		}
+		/*
+		 * Start searching for next token immediately after the first
+		 * "whitespace" character that follows this token.
+		 */
+		m = p + 1;
+	}
+
+	if (!saw_any_target) {
+		fprintf(stderr, "fixdep: parse error; no targets found\n");
+		exit(1);
+	}
+
+	printf("\n%s: $(deps_%s)\n\n", target, target);
+	printf("$(deps_%s):\n", target);
+}
+
+static void print_deps(void)
+{
+	struct stat st;
+	int fd;
+	void *map;
+
+	fd = open(depfile, O_RDONLY);
+	if (fd < 0) {
+		fprintf(stderr, "fixdep: error opening depfile: ");
+		perror(depfile);
+		exit(2);
+	}
+	if (fstat(fd, &st) < 0) {
+		fprintf(stderr, "fixdep: error fstat'ing depfile: ");
+		perror(depfile);
+		exit(2);
+	}
+	if (st.st_size == 0) {
+		fprintf(stderr, "fixdep: %s is empty\n", depfile);
+		close(fd);
+		return;
+	}
+	map = mmap(NULL, st.st_size, PROT_READ, MAP_PRIVATE, fd, 0);
+	if ((long) map == -1) {
+		perror("fixdep: mmap");
+		close(fd);
+		return;
+	}
+
+	parse_dep_file(map, st.st_size);
+
+	munmap(map, st.st_size);
+
+	close(fd);
+}
+
+int main(int argc, char **argv)
+{
+	if (argc != 4)
+		usage();
+
+	depfile = argv[1];
+	target  = argv[2];
+	cmdline = argv[3];
+
+	print_cmdline();
+	print_deps();
+
+	return 0;
+}
diff --git a/tools/build/tests/ex/Build b/tools/build/tests/ex/Build
new file mode 100644
index 0000000..4d502f9
--- /dev/null
+++ b/tools/build/tests/ex/Build
@@ -0,0 +1,11 @@
+ex-y += ex.o
+ex-y += a.o
+ex-y += b.o
+ex-y += b.o
+ex-y += empty/
+ex-y += empty2/
+ex-y += inc.o
+
+libex-y += c.o
+libex-y += d.o
+libex-y += arch/
diff --git a/tools/build/tests/ex/Makefile b/tools/build/tests/ex/Makefile
new file mode 100644
index 0000000..fee032e
--- /dev/null
+++ b/tools/build/tests/ex/Makefile
@@ -0,0 +1,27 @@
+# SPDX-License-Identifier: GPL-2.0
+export srctree := $(abspath ../../../..)
+export CC      := gcc
+export LD      := ld
+export AR      := ar
+
+ex:
+
+include $(srctree)/tools/build/Makefile.include
+
+ex: ex-in.o libex-in.o
+	$(CC) -o $@ $^
+
+ex.%: fixdep FORCE
+	make -f $(srctree)/tools/build/Makefile.build dir=. $@
+
+ex-in.o: fixdep FORCE
+	make $(build)=ex
+
+libex-in.o: fixdep FORCE
+	make $(build)=libex
+
+clean:
+	find . -name '*.o' -delete -o -name '\.*.cmd' -delete -o -name '\.*.d' -delete
+	rm -f ex ex.i ex.s
+
+.PHONY: FORCE
diff --git a/tools/build/tests/ex/a.c b/tools/build/tests/ex/a.c
new file mode 100644
index 0000000..66017a9
--- /dev/null
+++ b/tools/build/tests/ex/a.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int a(void)
+{
+	return 0;
+}
diff --git a/tools/build/tests/ex/arch/Build b/tools/build/tests/ex/arch/Build
new file mode 100644
index 0000000..5550618
--- /dev/null
+++ b/tools/build/tests/ex/arch/Build
@@ -0,0 +1,2 @@
+libex-y += e.o
+libex-y += f.o
diff --git a/tools/build/tests/ex/arch/e.c b/tools/build/tests/ex/arch/e.c
new file mode 100644
index 0000000..f6ef585
--- /dev/null
+++ b/tools/build/tests/ex/arch/e.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int e(void)
+{
+	return 0;
+}
diff --git a/tools/build/tests/ex/arch/f.c b/tools/build/tests/ex/arch/f.c
new file mode 100644
index 0000000..bffd9c6
--- /dev/null
+++ b/tools/build/tests/ex/arch/f.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int f(void)
+{
+	return 0;
+}
diff --git a/tools/build/tests/ex/b.c b/tools/build/tests/ex/b.c
new file mode 100644
index 0000000..2b29fb4
--- /dev/null
+++ b/tools/build/tests/ex/b.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int b(void)
+{
+	return 0;
+}
diff --git a/tools/build/tests/ex/c.c b/tools/build/tests/ex/c.c
new file mode 100644
index 0000000..a63b20a
--- /dev/null
+++ b/tools/build/tests/ex/c.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int c(void)
+{
+	return 0;
+}
diff --git a/tools/build/tests/ex/d.c b/tools/build/tests/ex/d.c
new file mode 100644
index 0000000..e114e8d
--- /dev/null
+++ b/tools/build/tests/ex/d.c
@@ -0,0 +1,6 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int d(void)
+{
+	return 0;
+}
diff --git a/tools/build/tests/ex/empty/Build b/tools/build/tests/ex/empty/Build
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/tools/build/tests/ex/empty/Build
diff --git a/tools/build/tests/ex/empty2/README b/tools/build/tests/ex/empty2/README
new file mode 100644
index 0000000..2107cc5
--- /dev/null
+++ b/tools/build/tests/ex/empty2/README
@@ -0,0 +1,2 @@
+This directory is left intentionally without Build file
+to test proper nesting into Build-less directories.
diff --git a/tools/build/tests/ex/ex.c b/tools/build/tests/ex/ex.c
new file mode 100644
index 0000000..3c02756
--- /dev/null
+++ b/tools/build/tests/ex/ex.c
@@ -0,0 +1,22 @@
+// SPDX-License-Identifier: GPL-2.0
+
+int a(void);
+int b(void);
+int c(void);
+int d(void);
+int e(void);
+int f(void);
+int inc(void);
+
+int main(void)
+{
+	a();
+	b();
+	c();
+	d();
+	e();
+	f();
+	inc();
+
+	return 0;
+}
diff --git a/tools/build/tests/ex/inc.c b/tools/build/tests/ex/inc.c
new file mode 100644
index 0000000..3636ab5
--- /dev/null
+++ b/tools/build/tests/ex/inc.c
@@ -0,0 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifdef INCLUDE
+#include "krava.h"
+#endif
+
+int inc(void)
+{
+	return 0;
+}
diff --git a/tools/build/tests/run.sh b/tools/build/tests/run.sh
new file mode 100755
index 0000000..2c54e4d
--- /dev/null
+++ b/tools/build/tests/run.sh
@@ -0,0 +1,70 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+function test_ex {
+	make -C ex V=1 clean > ex.out 2>&1
+	make -C ex V=1 >> ex.out 2>&1
+
+	if [ ! -x ./ex/ex ]; then
+	  echo FAILED
+	  exit -1
+	fi
+
+	make -C ex V=1 clean > /dev/null 2>&1
+	rm -f ex.out
+}
+
+function test_ex_suffix {
+	make -C ex V=1 clean > ex.out 2>&1
+
+	# use -rR to disable make's builtin rules
+	make -rR -C ex V=1 ex.o >> ex.out 2>&1
+	make -rR -C ex V=1 ex.i >> ex.out 2>&1
+	make -rR -C ex V=1 ex.s >> ex.out 2>&1
+
+	if [ -x ./ex/ex ]; then
+	  echo FAILED
+	  exit -1
+	fi
+
+	if [ ! -f ./ex/ex.o -o ! -f ./ex/ex.i -o ! -f ./ex/ex.s ]; then
+	  echo FAILED
+	  exit -1
+	fi
+
+	make -C ex V=1 clean > /dev/null 2>&1
+	rm -f ex.out
+}
+
+function test_ex_include {
+	make -C ex V=1 clean > ex.out 2>&1
+
+	# build with krava.h include
+	touch ex/krava.h
+	make -C ex V=1 CFLAGS=-DINCLUDE >> ex.out 2>&1
+
+	if [ ! -x ./ex/ex ]; then
+	  echo FAILED
+	  exit -1
+	fi
+
+	# build without the include
+	rm -f ex/krava.h ex/ex
+	make -C ex V=1 >> ex.out 2>&1
+
+	if [ ! -x ./ex/ex ]; then
+	  echo FAILED
+	  exit -1
+	fi
+
+	make -C ex V=1 clean > /dev/null 2>&1
+	rm -f ex.out
+}
+
+echo -n Testing..
+
+test_ex
+test_ex_suffix
+test_ex_include
+
+echo OK