scripts: test clean build when config is changed

If there is a change in the config directory the build test
will refresh the tested build config to take into account new options.
The git working directory and the last git commit are checked for a
change in config/.

Signed-off-by: Thomas Monjalon <thomas.monjalon@6wind.com>

scripts/test-build.sh

@@ -130,7 +130,12 @@ reset_env ()
 
 config () # <directory> <target> <options>
 {
-	if [ ! -e $1/.config ] ; then
+	reconfig=false
+	if git rev-parse 2>&- && [ -n "$(git diff HEAD~ -- config)" ] ; then
+		echo 'Default config may have changed'
+		reconfig=true
+	fi
+	if [ ! -e $1/.config ] || $reconfig ; then
 		echo "================== Configure $1"
 		make T=$2 O=$1 config