[aravis] Don't use APPDATA_XML_RULES unless APPDATA_XML is defined

[Emmanuel Pacaud <emmanuel src gnome org>]

commit f9f336295b7e66e9ede614392e41afbd1c1de430
Author: Patrick Doyle <wpd harvestai com>
Date:   Thu Oct 30 13:36:07 2014 -0400

    Don't use APPDATA_XML_RULES unless APPDATA_XML is defined

 configure.ac |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)
---
diff --git a/configure.ac b/configure.ac
index 6b6d37d..14c7caa 100644
--- a/configure.ac
+++ b/configure.ac
@@ -173,6 +173,12 @@ GOBJECT_INTROSPECTION_CHECK([0.10.0])
 GTK_DOC_CHECK([1.14],[--flavour no-tmpl])
 AM_CONDITIONAL([BUILD_GTK_DOC], [test "x$enable_gtk_doc" = "xyes" || test ! -f "autogen.sh"])
 
+ifdef(`APPDATA_XML','',
+[
+AC_DEFUN([APPDATA_XML],
+[
+  AC_SUBST(APPDATA_XML_RULES)
+])])
 APPDATA_XML
 
 AC_CONFIG_FILES([