From bda3095280a639306b889f5a8856bee4b81c7179 Mon Sep 17 00:00:00 2001
From: Pro-pra <pro2_2000@mail.ru>
Date: Thu, 14 Oct 2021 12:55:07 +0900
Subject: [PATCH] improve check ACLOCAL_AMFLAGS

This code from https://github.com/mate-desktop/mate-common/blob/aa57109bc472ea9340020d819b26d511fb3e002c/macros/mate-common.m4#L25

on my build farm ACLOCAL_AMFLAGS not recognized, and on make stage i see aclocal-1.16 -I  is missing argument
---
 configure.ac | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/configure.ac b/configure.ac
index 987c79133..038aee2ba 100644
--- a/configure.ac
+++ b/configure.ac
@@ -43,7 +43,13 @@ MUFFIN_PLUGIN_DIR="$libdir/$PACKAGE/plugins"
 AC_SUBST(MUFFIN_PLUGIN_DIR)
 
 # Honor aclocal flags
-AC_SUBST([ACLOCAL_AMFLAGS], ["-I $ac_macro_dir \${ACLOCAL_FLAGS}"])
+  dnl ensure that when the Automake generated makefile calls aclocal,
+  dnl it honours the $ACLOCAL_FLAGS environment variable
+  ACLOCAL_AMFLAGS="\${ACLOCAL_FLAGS}"
+  if test -n "$ac_macro_dir"; then
+    ACLOCAL_AMFLAGS="-I $ac_macro_dir $ACLOCAL_AMFLAGS"
+  fi
+  AC_SUBST([ACLOCAL_AMFLAGS])
 
 GETTEXT_PACKAGE=muffin
 AC_SUBST(GETTEXT_PACKAGE)