Fix name mangling for chkstk.
Seems that ___chkstk_ms
is handwritten assembly and so doesn't adhere to the C name mangling.
Tamar@Rage ~/ghc> nm -g "inplace\mingw\lib\gcc\x86_64-w64-mingw32\7.2.0\libgcc.a" | grep chkstk
_chkstk.o:
0000000000000004 T ___chkstk
_chkstk_ms.o:
0000000000000000 T ___chkstk_ms
Tamar@Rage ~/ghc> nm -g "inplace\mingw\lib\gcc\i686-w64-mingw32\7.2.0\libgcc.a" | grep chkstk
_chkstk.o:
00000000 T ___chkstk
_chkstk_ms.o:
00000000 T ___chkstk_ms
Before when doing checks on x86_64
it seems that the expansion that was there was generated by
the stack allocation code that uses alloca
expansion and not from the register allocator's
spilling.
This fixes the case where even on x86_64
we spill (mostly happens with profiling builds).