[geocode-glib] build: Clean m4 directory on maintainer-clean

[Philip Withnall <pwithnall src gnome org>]

commit 0dfe4a20cf1d0606abdc8d38ce1ef98ebe9d7bcd
Author: Philip Withnall <philip withnall collabora co uk>
Date:   Fri Oct 14 12:48:31 2016 +0100

    build: Clean m4 directory on maintainer-clean
    
    It should be deleted then.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=772928

 Makefile.am |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index b1cf087..154e601 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -23,6 +23,7 @@ MAINTAINERCLEANFILES = \
        gtk-doc.make \
        ABOUT-NLS \
        config.rpath \
+       m4/ \
        po/Makevars.template \
        po/Rules-quot \
        po/boldquot.sed \