[PATCH v2 0/1] MR2540: include: Define __has_attribute() if the compiler does not provide it.

[Zebediah Figura (＠zfigura)]

Fixes: f4c3801495f4fe17a10e2f21339de3b511c78339

Wine-Bug: https://bugs.winehq.org/show_bug.cgi?id=54666

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  v2: include: Include corecrt.h in vadefs.h

https://gitlab.winehq.org/wine/wine/-/merge_requests/2540