[rhythmbox] Create the m4 dir to prevent gtkdocize failing.

[Rodney Dawes <dobey src gnome org>]

commit 3e737302879bb7f6f854a49d4793be89a309fc53
Author: Rodney Dawes <dobey gnome org>
Date:   Wed May 15 17:13:56 2013 -0400

    Create the m4 dir to prevent gtkdocize failing.

 autogen.sh |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/autogen.sh b/autogen.sh
index 4e3341c..0e77a1c 100755
--- a/autogen.sh
+++ b/autogen.sh
@@ -30,6 +30,9 @@ if test -z `which autopoint`; then
         exit 1
 fi
 
+# Need to mkdir -p the m4 directory in case it doesn't exist, to prevent
+# gtkdocize from failing.
+mkdir -p m4
 gtkdocize || exit $?
 autopoint --force
 AUTOPOINT='intltoolize --automake --copy' autoreconf --force --install --verbose