[gnome-software/gnome-3-20] trivial: Fix the xdg-app build

[Richard Hughes <rhughes src gnome org>]

commit d4bc47fcd3a3fc968006ceedd45ef0f9bc0898c3
Author: Richard Hughes <richard hughsie com>
Date:   Thu Apr 7 17:13:45 2016 +0100

    trivial: Fix the xdg-app build

 src/plugins/Makefile.am |    5 ++++-
 1 files changed, 4 insertions(+), 1 deletions(-)
---
diff --git a/src/plugins/Makefile.am b/src/plugins/Makefile.am
index 71b78b0..77e065b 100644
--- a/src/plugins/Makefile.am
+++ b/src/plugins/Makefile.am
@@ -118,7 +118,10 @@ libgs_plugin_limba_la_CFLAGS = $(GS_PLUGIN_CFLAGS) $(WARN_CFLAGS)
 endif
 
 if HAVE_XDG_APP
-libgs_plugin_xdg_app_la_SOURCES = gs-plugin-xdg-app.c
+libgs_plugin_xdg_app_la_SOURCES =                      \
+       gs-appstream.c                                  \
+       gs-appstream.h                                  \
+       gs-plugin-xdg-app.c
 libgs_plugin_xdg_app_la_LIBADD = $(GS_PLUGIN_LIBS) $(XDG_APP_LIBS)
 libgs_plugin_xdg_app_la_LDFLAGS = -module -avoid-version
 libgs_plugin_xdg_app_la_CFLAGS = $(GS_PLUGIN_CFLAGS) $(WARN_CFLAGS)