It seems that in MSVC timeval's tv_sec field is of type long.
localtime() takes a time_t pointer.  Since long is 32-bit even on 64-bit
builds in MSVC, passing a long pointer instead of the correct time_t
pointer generated a compiler warning.  Fix that.

Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/CAApHDvoRG25X_=ZCGSPb4KN_j2iu=G2uXsRSg8NBZeuhkOSETg@mail.gmail.com