possible bug in rc 1.4

[malte@TechFak.Uni-Bielefeld.DE]

Hello fellow rc users,

I'm afraid that I've found a bug in rc that I can easily reproduce on
Sparcs running Solaris 2.[2] and RS6000 running AIX 3.2.5, but not on
Sparcs running SunOS 4, DEC Alphas running OSF/1 1.3 and SGIs running
IRIX 4.0.5. On all machines, gcc 2.5.3 was used to compile the shell.

Consider running the following script:

	#!/vol/local/bin/rc
	fn sigint sighup { echo something >[1=2]; exit 1 }
	while(){}

	; script
	[ run run run ]
	^Csomething
	;

Now I add sighup to the list of caught signals, rerun the script and
hit ^C again, the output is either "something" or
	rc panic: unexpected node in doredirs!
or "something" followed by some blanks and newlines.
and is not reproducible. Adding another signal consistently causes an rc
panic. I believe that either r or r->r in doredirs gets corrupted but have
no idea why.
If I replace the invocation of echo with a call to another function echo'ing
the message with redirection, everything is fine.

Malte