Enable global signal distribution in htl

Enable global signal distribution in htl

* sysdeps/mach/hurd/htl/pt-sigstate-init.c (__pthread_sigstate_init):
Call _hurd_sigstate_set_global_rcv().
* sysdeps/mach/hurd/htl/pt-sigstate-destroy.c
(__pthread_sigstate_destroy): Call _hurd_sigstate_delete().
* sysdeps/mach/hurd/htl/pt-sigstate.c: Include <hurd/msg.h>
(__pthread_sigstate): Use _hurd_sigstate_lock()/_hurd_sigstate_unlock()
and _hurd_sigstate_pending(). Call __msg_sig_post() to wake up thread
with pending signals.
* sysdeps/mach/hurd/Makefile (LDLIBS-pthread.so): Add
$(objdir)/hurd/libhurduser.so.

Gbp-Pq: Topic hurd-i386
Gbp-Pq: Name libpthread_sigs.diff