[gnome-photos] build: Ignore the M4 sources pulled in by Gettext

[Debarshi Ray <debarshir src gnome org>]

commit 0959490060285154a039716366b883496e79eea9
Author: Debarshi Ray <debarshir gnome org>
Date:   Mon Oct 30 13:51:30 2017 +0100

    build: Ignore the M4 sources pulled in by Gettext

 Makefile.am |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/Makefile.am b/Makefile.am
index 6e77e6b..ab4cf26 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -26,6 +26,7 @@ DISTCLEANFILES = \
        $(NULL)
 
 MAINTAINERCLEANFILES = \
+       $(GITIGNORE_MAINTAINERCLEANFILES_M4_GETTEXT) \
        $(srcdir)/AUTHORS \
        $(srcdir)/INSTALL \
        $(srcdir)/ar-lib \