[Issue 23701] ImportC: __int64 is not documented as supported Visual C extension

[d-bugmail at puremagic.com]

https://issues.dlang.org/show_bug.cgi?id=23701

--- Comment #3 from Walter Bright <bugzilla at digitalmars.com> ---
I take that back. importc.h has a #define for it:

    #define __int64 long long

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