FD_SETSIZE needs to be declared before winsock2.h, or it is possible to
run into buffer overflow issues when using --jobs. This is similar to
pgbench's solution done in
a23c641.
This has been introduced by
71d84ef, and older versions have been using
the default value of FD_SETSIZE, defined at 64.
Per buildfarm member jacana, but this impacts all Windows animals
running the TAP tests. I have reproduced the failure locally to check
the patch.
Author: Michael Paquier
Reviewed-by: Andrew Dunstan
Discussion: https://postgr.es/m/
20190826054000.GE7005@paquier.xyz
Backpatch-through: 9.5