glib-compile-schemas: ignore qualified tags/attrs

Ignore qualified (in the XML namespace sense) tags and attributes when
compiling GSettings schemas.

This will allow people to add custom tags and attributes to their schemas
without tripping up the compiler.

https://bugzilla.gnome.org/show_bug.cgi?id=635641

gio/glib-compile-schemas.c

@@ -1728,7 +1728,8 @@ parse_gschema_files (gchar    **files,
 
       context = g_markup_parse_context_new (&parser,
                                             G_MARKUP_TREAT_CDATA_AS_TEXT |
-                                            G_MARKUP_PREFIX_ERROR_POSITION,
+                                            G_MARKUP_PREFIX_ERROR_POSITION |
+                                            G_MARKUP_IGNORE_QUALIFIED,
                                             &state, NULL);