Merge remote-tracking branch 'origin/pr/2647' into development

* origin/pr/2647:
  list-symbols.sh: if the build fails, print the build transcript
  Document "check-names.sh -v"
  all.sh: invoke check-names.sh in print-trace-on-exit mode
  Print a command trace if the check-names.sh exits unexpectedly
diff --git a/tests/scripts/all.sh b/tests/scripts/all.sh
index 369df15..c234ea2 100755
--- a/tests/scripts/all.sh
+++ b/tests/scripts/all.sh
@@ -597,7 +597,7 @@
 
 component_check_names () {
     msg "test/build: declared and exported names" # < 3s
-    record_status tests/scripts/check-names.sh
+    record_status tests/scripts/check-names.sh -v
 }
 
 component_check_doxygen_warnings () {
diff --git a/tests/scripts/check-names.sh b/tests/scripts/check-names.sh
index f18a162..90ecfd2 100755
--- a/tests/scripts/check-names.sh
+++ b/tests/scripts/check-names.sh
@@ -2,26 +2,42 @@
 #
 # This file is part of mbed TLS (https://tls.mbed.org)
 #
-# Copyright (c) 2015-2016, ARM Limited, All Rights Reserved
-#
-# Purpose
-#
-# This script confirms that the naming of all symbols and identifiers in mbed
-# TLS are consistent with the house style and are also self-consistent.
-#
+# Copyright (c) 2015-2019, ARM Limited, All Rights Reserved
+
 set -eu
 
+if [ $# -ne 0 ] && [ "$1" = "--help" ]; then
+    cat <<EOF
+$0 [-v]
+This script confirms that the naming of all symbols and identifiers in mbed
+TLS are consistent with the house style and are also self-consistent.
+
+  -v    If the script fails unexpectedly, print a command trace.
+EOF
+    exit
+fi
+
 if grep --version|head -n1|grep GNU >/dev/null; then :; else
     echo "This script requires GNU grep.">&2
     exit 1
 fi
 
+trace=
+if [ $# -ne 0 ] && [ "$1" = "-v" ]; then
+  shift
+  trace='-x'
+  exec 2>check-names.err
+  trap 'echo "FAILED UNEXPECTEDLY, status=$?";
+        cat check-names.err' EXIT
+  set -x
+fi
+
 printf "Analysing source code...\n"
 
-tests/scripts/list-macros.sh
+sh $trace tests/scripts/list-macros.sh
 tests/scripts/list-enum-consts.pl
-tests/scripts/list-identifiers.sh
-tests/scripts/list-symbols.sh
+sh $trace tests/scripts/list-identifiers.sh
+sh $trace tests/scripts/list-symbols.sh
 
 FAIL=0
 
@@ -82,6 +98,12 @@
     FAIL=1
 fi
 
+if [ -n "$trace" ]; then
+  set +x
+  trap - EXIT
+  rm check-names.err
+fi
+
 printf "\nOverall: "
 if [ "$FAIL" -eq 0 ]; then
     rm macros actual-macros enum-consts identifiers exported-symbols
diff --git a/tests/scripts/list-symbols.sh b/tests/scripts/list-symbols.sh
index c258719..ffdce8f 100755
--- a/tests/scripts/list-symbols.sh
+++ b/tests/scripts/list-symbols.sh
@@ -14,8 +14,20 @@
 
 cp include/mbedtls/config.h include/mbedtls/config.h.bak
 scripts/config.pl full
-CFLAGS=-fno-asynchronous-unwind-tables make clean lib >/dev/null 2>&1
+make_ret=
+CFLAGS=-fno-asynchronous-unwind-tables make clean lib \
+      >list-symbols.make.log 2>&1 ||
+  {
+    make_ret=$?
+    echo "Build failure: CFLAGS=-fno-asynchronous-unwind-tables make clean lib"
+    cat list-symbols.make.log >&2
+  }
+rm list-symbols.make.log
 mv include/mbedtls/config.h.bak include/mbedtls/config.h
+if [ -n "$make_ret" ]; then
+    exit "$make_ret"
+fi
+
 if uname | grep -F Darwin >/dev/null; then
     nm -gUj library/libmbed*.a 2>/dev/null | sed -n -e 's/^_//p'
 elif uname | grep -F Linux >/dev/null; then