Implement JIT for MinGW-w64 64-bit
https://bugs.webkit.org/show_bug.cgi?id=114580

Patch by Jonathan Liu <net147@gmail.com> on 2013-04-18
Reviewed by Jocelyn Turcotte.

* jit/JITStubs.cpp:
(JSC):

git-svn-id: http://svn.webkit.org/repository/webkit/trunk@148663 268f45cc-cd09-0410-ab3c-d52691b4dbfc