move ports into its own gyp file


git-svn-id: http://skia.googlecode.com/svn/trunk@2874 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/gyp/iOSSampleApp.gyp b/gyp/iOSSampleApp.gyp
index 4fe7fe2..84708bb 100644
--- a/gyp/iOSSampleApp.gyp
+++ b/gyp/iOSSampleApp.gyp
@@ -149,6 +149,7 @@
         'core.gyp:core',
         'effects.gyp:effects',
         'images.gyp:images',
+        'ports.gyp:ports',
         'views.gyp:views',
         'utils.gyp:utils',
         'animator.gyp:animator',