Run webkit-build --gtk and you'll see each time that generated files are generated over and over.
Got this fixed in a local working copy, will upload the fix shortly.
Created attachment 201355 [details] Patch
Comment on attachment 201355 [details] Patch Thanks!
Comment on attachment 201355 [details] Patch Clearing flags on attachment: 201355 Committed r149887: <http://trac.webkit.org/changeset/149887>
All reviewed patches have been landed. Closing bug.