^G while inside UNWIND-PROTECT

[RLB at MIT-MC (Richard L. Bryan)]

Well, maybe the situation is well defined, but I still get MPV and sometimes
PURPG traps when I attempt the quit.  Specifically, type at a bare Lisp,

(defun x ()
       (*catch 'foo (unwind-protect (+ 0 0.0)
				    (nointerrupt ())
				    (*throw 'foo 'foo))))))

Just run (X) and at the ;WRNG-TYPE-ARG type ^G.
Obviously, $P never wins. Sometimes $G wins, sometimes 100$G wins,
and sometimes even 100$G loses.  I haven't figured out just how
to reproduce all these.

JONL, you said someone was pushing an extra word on INTPDL?