[mutter] build: Create m4 directory

[Colin Walters <walters src gnome org>]

commit 207fdd4a342a2e9d0891c4c8b1e6b14aedf55df6
Author: Seán de Búrca <leftmostcat gmail com>
Date:   Mon Aug 26 06:47:13 2013 -0400

    build: Create m4 directory
    
    Due to changes in gnome-common git, an implicit m4 directory is no
    longer created during autogen. The attached patch explicitly and
    correctly specifies a macro directory.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=706787

 Makefile.am  |    2 ++
 configure.ac |    1 +
 2 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 56c7c88..223b44b 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -1,6 +1,8 @@
 
 SUBDIRS=src po doc
 
+ACLOCAL_AMFLAGS = -I m4 ${ACLOCAL_FLAGS}
+
 EXTRA_DIST = HACKING MAINTAINERS rationales.txt
 
 DISTCLEANFILES = intltool-extract intltool-merge intltool-update po/stamp-it po/.intltool-merge-cache
diff --git a/configure.ac b/configure.ac
index 7ea4930..4d1875f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -12,6 +12,7 @@ m4_define([mutter_plugin_api_version], [3])
 AC_INIT([mutter], [mutter_version],
         [http://bugzilla.gnome.org/enter_bug.cgi?product=mutter])
 
+AC_CONFIG_MACRO_DIR([m4])
 AC_CONFIG_SRCDIR(src/core/display.c)
 AC_CONFIG_HEADERS(config.h)