diff --git a/configure b/configure
index f770ae1..d3e3c7d 100755
--- a/configure
+++ b/configure
@@ -634,7 +634,7 @@ common_defaults()
 	# debug
 	if [ _$mb_debug = _yes ]; then
 		if [ -z "$mb_cflags_debug" ]; then
-			mb_cflags_debug='-g3 -O0'
+			mb_cflags_debug='$(_CFLAGS_g3) $(_CFLAGS_O0)'
 		fi
 	fi