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.)

resolv/gai_sigqueue.c

@@ -27,5 +27,5 @@ __gai_sigqueue (int sig, const union sigval val, pid_t caller_pid)
   __set_errno (ENOSYS);
   return -1;
 }
-
+libc_hidden_def (__gai_sigqueue)
 stub_warning (__gai_sigqueue)