gpac: scope patches to stable

Formula/gpac.rb

@@ -10,9 +10,15 @@ require 'formula'
 
 class Gpac < Formula
   homepage 'http://gpac.wp.mines-telecom.fr/'
+
+  stable do
     url 'https://downloads.sourceforge.net/gpac/gpac-0.5.0.tar.gz'
     sha1 '48ba16272bfa153abb281ff8ed31b5dddf60cf20'
 
+    # Fixes build against ffmpeg 2.x; backported from upstream SVN
+    patch :DATA
+  end
+
   head 'https://gpac.svn.sourceforge.net/svnroot/gpac/trunk/gpac'
 
   depends_on :x11 => :recommended
@@ -29,9 +35,6 @@ class Gpac < Formula
   depends_on 'ffmpeg' => :optional
   depends_on 'openjpeg' => :optional
 
-  # Fixes build against ffmpeg 2.x; backported from upstream SVN
-  patch :DATA
-
   def install
     ENV.deparallelize