resolv: Move libanl into libc (if libpthread is in libc)

The symbols gai_cancel, gai_error, gai_suspend, getaddrinfo_a,
__gai_suspend_time64 were moved using scripts/move-symbol-to-libc.py.

For Hurd (which remains !PTHREAD_IN_LIBC), a few #define redirects
had to be added because several pthread functions are not available
under __.  (Linux uses __ prefixes for most hidden aliases, and has
to in some cases to avoid linknamespace issues.)