Originally http://trac.webkit.org/changeset/139612 introduced this optimization, but lost it with http://trac.webkit.org/changeset/181690. We don't need to run autogen.sh and it is very slow on cross builder ARM bots. The build time is longer with 10-15 minutes for nothing now.
Created attachment 250066 [details] Patch
Comment on attachment 250066 [details] Patch Clearing flags on attachment: 250066 Committed r182317: <http://trac.webkit.org/changeset/182317>
All reviewed patches have been landed. Closing bug.