diff --git a/configure.ac b/configure.ac
index 3ac3f12..b1625a1 100644
--- a/configure.ac
+++ b/configure.ac
@@ -88,7 +88,7 @@ AC_ARG_ENABLE([debug],
 	[debug=${enableval}], [debug=no])
 
 if test "x${debug}" = xyes; then
-	CFLAGS="$CFLAGS -g"
+	CFLAGS="$CFLAGS -g -DDEBUG"
 fi
 
 AC_ARG_ENABLE([asan],