[Bug rust/109853] WIN64 is a predefined constant by GCC on MinGW-w64

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109853

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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             Target|                            |mingw-w64

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Eh.  It's of course equally bad to have a predefined macro in the
non-implementation namespace (but possibly it's required for MSVC
compatibility).