GnuWin32 doesn't distribute bison 2.3 any more. Making WebKit work with bison 2.1 is easier than compiling bison 2.3 ourselves.
Created attachment 260459 [details] Patch
Comment on attachment 260459 [details] Patch Clearing flags on attachment: 260459 Committed r189267: <http://trac.webkit.org/changeset/189267>
All reviewed patches have been landed. Closing bug.