* sysdeps/mach/hurd/fork.c (LOSE): Put `goto lose' in dead code

* sysdeps/mach/hurd/fork.c (LOSE): Put `goto lose' in dead code

	so the label is not considered unused.

	* sysdeps/mach/hurd/pwrite64.c: New file.
	* sysdeps/mach/hurd/pread64.c: New file.

	* sysdeps/mach/hurd/pread.c
	(__libc_pread): Define this name, with __pread as an alias.
	* sysdeps/mach/hurd/pwrite.c
	(__libc_pwrite): Define this name, with __pwrite as an alias.

	Implement POSIX "shared memory objects" as regular
	files residing in the /var/run/shm/ directory.
	This works on any system that supports _POSIX_MAPPED_FILES,
	to make it also support _POSIX_SHARED_MEMORY_OBJECTS.
	* sysdeps/posix/shm_open.c: New file.
	* sysdeps/posix/shm_unlink.c: New file.
	* sysdeps/mach/hurd/bits/posix_opt.h
	(_POSIX_SHARED_MEMORY_OBJECTS): Define it.

	* rt/aio_notify.c (__aio_notify_only) [! _POSIX_REALTIME_SIGNALS]:
	Use raise instead of __aio_sigqueue.