The header, which is actually typedefs HANDLE , is winnt.h . Unfortunately, this is 15K lines here, so fixing your problem by including slimline windef.h bit misleading.
Here is the relevant part of my system (obviously, the details may change from revision to revision, but will not change at the implementation level, as this will violate existing binaries):
PS you need to love #if 0 in this Microsoft header shipping file.
Steve townsend
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