Reproducible segmentation fault with "cother".

Hello,

I've written a small script that makes the ratpoison's window ordering
more logical to me. (Allowing me to insert windows between any two
windows in the window list). While running it, I noticed that
ratpoison would sometimes seg fault. I tracked it down to a call to
"cother". I am able to reproduce it with the following steps:

1. Start ratpoison with nothing running, so that there is only a
default group with no windows.
2. Hit "C-t !" and enter "ratpoison -c cother".
3. Ratpoison will seg fault.

Here's the backtrace:

Program received signal SIGSEGV, Segmentation fault.
0x0000000000405640 in cmd_cother ()
#0  0x0000000000405640 in cmd_cother ()
No symbol table info available.
#1  0x000000000040e7e9 in command ()
No symbol table info available.
#2  0x00000000004130c9 in T.123 ()
No symbol table info available.
#3  0x0000000000413771 in listen_for_events ()
No symbol table info available.
#4  0x00000000004196bd in main ()
No symbol table info available.

Hopefully, this is reproducible on your computers too. If not, I can
provide more information as needed.

Eric