Avoid -Wcast-function-type warnings from casts after GetProcAddress. Reported by Andy Moreton <andrewjmoreton@gmail.com> in <https://lists.gnu.org/archive/html/emacs-devel/2018-08/msg00468.html>. Solution proposed by Eli Zaretskii. * lib/getaddrinfo.c (GetProcAddress): Cast result to 'void *' first. * lib/gettimeofday.c (GetProcAddress): Likewise. * lib/link.c (GetProcAddress): Likewise. * lib/physmem.c (GetProcAddress): Likewise. * lib/poll.c (GetProcAddress): Likewise. * lib/select.c (GetProcAddress): Likewise. * lib/stat-w32.c (GetProcAddress): Likewise.