stat() on Windows might cause error if target file is larger than 4GB

Hi,

This mail is about following bug report post:
https://www.postgresql.org/message-id/flat/153442391458.1505.9181095584291689853%40wrigleys.postgresql.org

When pg_dump has '--format=directory' option and the dump file size become
4GB over, the strange error message 'Unknown error' will be output.

This is because _stat64i32() is used for stat() on Windows, I think.
Seeing following URL, _stat64i32() could use 32 bit, it means 4GB is max size.
https://msdn.microsoft.com/en-us/library/14h5k7ff.aspx

When I create the simple application to use stat() on VS2013,
stat() could not deal with 4GB file and failed with errno=132.
I think the pg_dump occurs EOVERFLOW, but Windows' errno.h does not have
this errno, so 'Unknown error' is output.

So, pgwin32_safestat() should be changed to solve this problem.
Do you have any idea or comments?

Regards,
Daisuke Higuchi