We need to ensure our CFLAGS are preserved as well as whatever tweak configure
tries to make. Without these, the debug prefix changes get lost and we lose
build reproducibility, likely with other side effects.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
Upstream-Status: Pending
2020/1/27

Index: kbd-2.2.0/configure.ac
===================================================================
--- kbd-2.2.0.orig/configure.ac
+++ kbd-2.2.0/configure.ac
@@ -72,9 +72,9 @@ if test "$enable_code_coverage" = yes; t
 fi
 
 case "$GCC,$ac_cv_prog_cc_g" in
-	yes,yes) CFLAGS="-g $CC_O_LEVEL $FORTIFY_SOURCE" ;;
-	yes,)    CFLAGS="$CC_O_LEVEL $FORTIFY_SOURCE" ;;
-	   ,yes) CFLAGS="-g" ;;
+	yes,yes) CFLAGS="-g $CC_O_LEVEL $FORTIFY_SOURCE $CFLAGS" ;;
+	yes,)    CFLAGS="$CC_O_LEVEL $FORTIFY_SOURCE $CFLAGS" ;;
+	   ,yes) CFLAGS="-g $CFLAGS" ;;
 esac
 
 CC_CHECK_CFLAGS_APPEND([\