* hurd/hurdsig.c (_hurd_internal_post_signal): Don't loop to check
pending signals if the thread is in a critical section. It will
send us a msg when it finishes.
* sysdeps/mach/hurd/pathconf.c: New file.
* sysdeps/mach/hurd/fpathconf.c: New file.
* sysdeps/mach/hurd/sigaction.c: Only notify the proc server for
SIGCHLD when the SA_NOCLDSTOP bit actually changes.
