Hurd: Adapt to changed MIG output.

	gdb/
	* reply_mig_hack.awk: Don't expect to see the auto keyword.

Based on a patch by David Michael <fedora.dm0@gmail.com>.
Hurd: Make MIG output parsing more robust.

	gdb/
	* reply_mig_hack.awk: In phase 5, keep going if we have not yet
	collected the type check structures.

Based on a patch by David Michael <fedora.dm0@gmail.com>.
Hurd: New RPC reply stub functions.

	gdb/
	* gnu-nat.c (ill_rpc): Remove function; replaced with this...
	(ILL_RPC): ... new macro.
	(do_mach_notify_no_senders, do_mach_notify_port_deleted)
	(do_mach_notify_msg_accepted, do_mach_notify_port_destroyed)
	(do_mach_notify_send_once, S_proc_setmsgport_reply)
	(S_proc_getmsgport_reply, S_msg_sig_post_reply): Generate stub
	functions with ILL_RPC macro.
	(S_proc_pid2task_reply, S_proc_task2pid_reply)
	(S_proc_task2proc_reply, S_proc_proc2task_reply)
	(S_proc_pid2proc_reply, S_proc_getprocinfo_reply)
	(S_proc_getprocargs_reply, S_proc_getprocenv_reply)
	(S_proc_getloginid_reply, S_proc_getloginpids_reply)
	(S_proc_getlogin_reply, S_proc_getsid_reply)
	(S_proc_getsessionpgids_reply, S_proc_getsessionpids_reply)
	(S_proc_getsidport_reply, S_proc_getpgrp_reply)
	(S_proc_getpgrppids_reply, S_proc_get_tty_reply)
	(S_proc_getnports_reply, S_proc_is_important_reply)
	(S_proc_get_code_reply): New stub functions, generated with
	ILL_RPC macro.

Based on a patch by David Michael <fedora.dm0@gmail.com>.
Hurd: Adjust to startup-with-shell changes.

In commit 98882a26513e25b2161b41dfd4bed97b59b2c01a, STARTUP_WITH_SHELL was made
a runtime toggle, startup-with-shell.  The Hurd code was missed to be adjusted;
it had a value hard-coded instead of using START_INFERIOR_TRAPS_EXPECTED.  Fix
that, and also simplify gnu-nat's pending_execs handling from counting to just
a flag.

	gdb/
	* gnu-nat.c (struct inf): Change pending_execs member to a 1-bit
	flag.  Adjust all users; in particular...
	(gnu_wait): ..., don't decrement its value in here...
	(gnu_create_inferior): ..., and instead set the flag in here,
	around the startup_inferior call, and call that one with
	START_INFERIOR_TRAPS_EXPECTED.
ld: Remove Hurd-specific XFAILs related to weak symbols.

This has been fixed properly, in glibc.

	ld/testsuite/
	* ld-elfweak/elfweak.exp (setup_xfail_gnu_hurd): Remove function
	and all usage of it.