Make autotools warnings visible.

Change-Id: Ibcdac7100faca7a66d9b3440431e74a8a8c5f042
Signed-off-by: R. Diez <rdiezmail-openocd@yahoo.de>
Reviewed-on: http://openocd.zylin.com/5639
Tested-by: jenkins
Reviewed-by: Andreas Fritiofson <andreas.fritiofson@gmail.com>

bootstrap

@@ -24,11 +24,12 @@ fi
 # bootstrap the autotools
 (
 set -x
-aclocal
+aclocal --warnings=all
+# Apparently, not all versions of libtoolize support option --warnings=all .
 ${libtoolize} --automake --copy
-autoconf
-autoheader
-automake --gnu --add-missing --copy
+autoconf --warnings=all
+autoheader --warnings=all
+automake --warnings=all --gnu --add-missing --copy
 )
 
 if [ -n "$SKIP_SUBMODULE" ]; then