diff --git a/configure.ac b/configure.ac
index 0be7802..d19c8ec 100644
--- a/configure.ac
+++ b/configure.ac
@@ -50,7 +55,7 @@
 if test "x${REVISION}" != "xr0"
 then
 	# force debug mode for a SVN working copy
-	CFLAGS="-g -Wall"
+	CFLAGS+=" -Wall"
 else
 	REVISION="-1"
 fi