cmake support for host applications only (not TAs)

This introduces support for building the host part (what's running in
linux user space) of optee_examples using CMake. TAs are as before built
using TA dev kit.

Acked-by: Jerome Forissier <jerome.forissier@linaro.org>
Reviewed-by: Joakim Bech <joakim.bech@linaro.org>
Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org>
diff --git a/CMakeLists.txt b/CMakeLists.txt
new file mode 100644
index 0000000..b8879b8
--- /dev/null
+++ b/CMakeLists.txt
@@ -0,0 +1,33 @@
+cmake_minimum_required (VERSION 3.2)
+project (optee_examples C)
+
+# https://cmake.org/Wiki/CMake_Useful_Variables
+set (CMAKE_TOOLCHAIN_FILE CMakeToolchain.txt)
+
+include(GNUInstallDirs)
+
+add_compile_options (-Wall)
+#add_compile_options (
+#	-Wall -Wbad-function-cast -Wcast-align
+#	-Werror-implicit-function-declaration -Wextra
+#	-Wfloat-equal -Wformat-nonliteral -Wformat-security
+#	-Wformat=2 -Winit-self -Wmissing-declarations
+#	-Wmissing-format-attribute -Wmissing-include-dirs
+#	-Wmissing-noreturn -Wmissing-prototypes -Wnested-externs
+#	-Wpointer-arith -Wshadow -Wstrict-prototypes
+#	-Wswitch-default -Wunsafe-loop-optimizations
+#	-Wwrite-strings -Werror -fPIC
+#)
+
+find_program(CCACHE_FOUND ccache)
+if(CCACHE_FOUND)
+	set_property(GLOBAL PROPERTY RULE_LAUNCH_COMPILE ccache)
+	set_property(GLOBAL PROPERTY RULE_LAUNCH_LINK ccache)
+endif(CCACHE_FOUND)
+
+file(GLOB dirs *)
+foreach(dir ${dirs})
+	if(EXISTS ${dir}/CMakeLists.txt)
+		add_subdirectory(${dir})
+	endif()
+endforeach()