For 64-bit Windows, there is a potential problem in the use case:

• INT2FD with the return value from npth_accept

By the API of npth_accept, it returns type int, which may not be good when/if 64-bit value is used for SOCKET.

Candidates are:
(1) Change the API/ABI of nPth

• Remove INT2FD before npth_accept
• Change the API/ABI of npth_accept
  • let it return (void *) on Windows

(2) Use plain accept

• Remove INT2FD before npth_accept
• No use of npth_accept, but use the combo of npth_unprotect, accept, and npth_protect
  • Use a type conversion to (void *) from SOCKET to be gnupg_fd_t for accept

(3) No fix

• Ignore the fact that the masking to lower 32-bit occurs in npth_accept (from accept)