diff --git a/acinclude.m4 b/acinclude.m4
index ac29c2bb..d79458c5 100644
--- a/acinclude.m4
+++ b/acinclude.m4
@@ -15,7 +15,7 @@ AC_DEFUN([COMPILER_FLAGS], [
 		CFLAGS="-Wall -O2 -D_FORTIFY_SOURCE=2"
 	fi
 	if (test "$USE_MAINTAINER_MODE" = "yes"); then
-		CFLAGS="$CFLAGS -Werror -Wextra"
+		CFLAGS="$CFLAGS -Werror -Wextra -Wshadow"
 		CFLAGS="$CFLAGS -Wno-unused-parameter"
 		CFLAGS="$CFLAGS -Wno-missing-field-initializers"
 		CFLAGS="$CFLAGS -Wdeclaration-after-statement"