util/lint: Add lint rule to watch for Makefile.inc

This should keep new makefiles from being named Makefile.inc.

Change-Id: I4a47998e1c997b82b8a15319eae96cdc0de64e77
Signed-off-by: Martin Roth <gaumless@gmail.com>
Signed-off-by: Elyes Haouas <ehaouas@noos.fr>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/81857
Reviewed-by: Felix Singer <service+coreboot-gerrit@felixsinger.de>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Varshit Pandya <pandyavarshit@gmail.com>

util/lint/lint-stable-030-makefile-inc

@@ -0,0 +1,24 @@
+#!/usr/bin/env sh
+# SPDX-License-Identifier: GPL-2.0-or-later
+#
+# DESCR: Verify that Makefiles are not named Makefile.inc
+#
+
+LINTDIR="$(
+  cd -- "$(dirname "$0")" > /dev/null 2>&1 || return
+  pwd -P
+)"
+
+# shellcheck source=helper_functions.sh
+. "${LINTDIR}/helper_functions.sh"
+
+# Exit if the code isn't in a git repo
+if [ "${IN_GIT_TREE}" -eq 0 ]; then
+  exit 0
+fi
+
+MAKELIST="$(${FIND_FILES} | grep Makefile.inc)"
+if [ -n "${MAKELIST}" ]; then
+  echo "Error: Makefiles should be Makefile.mk not Makefile.inc"
+  echo "${MAKELIST}"
+fi