[MinGW] Enable large file for mingw-w64

64-bit mingw doesn't define _FILE_OFFSET_BITS=64 by default.

Differential Revision: https://reviews.llvm.org/D53569

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@345131 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed