New primitive NEW-MAKE-PIPE does what MAKE-PIPE does but stores its

New primitive NEW-MAKE-PIPE does what MAKE-PIPE does but stores its
results in weak pairs so that it can be used with GC finalizers.  Use
this in the runtime's MAKE-PIPE procedure so that interrupts need not
be disabled, and file descriptor exhaustion can trigger garbage
collection which can trigger GC daemons that close files.