[file-roller] configure.ac: added macro as described in gnome-common documentation

[Paolo Bacchilega <paobac src gnome org>]

commit 8d818c07ef6eeecef964ea0565108066e646d69b
Author: Paolo Bacchilega <paobac src gnome org>
Date:   Wed Aug 17 15:43:00 2016 +0200

    configure.ac: added macro as described in gnome-common documentation

 configure.ac |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index ce31736..cd85460 100644
--- a/configure.ac
+++ b/configure.ac
@@ -9,6 +9,7 @@ m4_ifdef([AM_SILENT_RULES], [AM_SILENT_RULES([yes])])
 AC_CONFIG_SRCDIR([config.h.in])
 AC_CONFIG_HEADER([config.h])
 AC_CONFIG_MACRO_DIR([m4])
+AC_SUBST([ACLOCAL_AMFLAGS], ["-I $ac_macro_dir \${ACLOCAL_FLAGS}"])
 
 AC_PROG_CC
 LT_INIT