version with zero args, so it should only be visible if __BSD_VISIBLE
(and not also for __XPG_VISIBLE). Contrawise, readlink() has been
part of base POSIX since 1995, so move to proper #if area for that.
Move crypt_checkpass() to the pure-BSD section of the file.
setpgrp() issue noted by Matti Karnaattu (mkarnaattu (at) gmail.com)
ok millert@