Needs wsutil/wsgetopt.h if the platform doesn't have getopt_long().

This includes Windows (which doesn't even have getopt()).

Change-Id: I01a3a9a00014176875ddad6760c387bf7aa9de84
Reviewed-on: https://code.wireshark.org/review/2804
Reviewed-by: Guy Harris <guy@alum.mit.edu>