intltool-update Vala support

The -m option (search for left out files from POTFILES.in) doesn't work with vala source files.

Even though more flexibility over the file extension whould be nice, it can be as easy as changing this for now:

=== modified file 'intltool-update.in'
--- intltool-update.in 2011-10-08 19:24:23 +0000
+++ intltool-update.in 2012-08-22 09:00:17 +0000
@@ -88,7 +88,7 @@
 "tlk(?:\\.in)+"; # Bioware Aurora Talk Table Format

 my $buildin_gettext_support =
-"c|y|cs|cc|cpp|c\\+\\+|h|hh|gob|py|scm(?:\\.in)*";
+"c|y|cs|cc|cpp|c\\+\\+|h|hh|gob|py|scm(?:\\.in)*|vala";

 ## Always flush buffer when printing
 $| = 1;