198.sysval test issue on Solaris

Hi,

I'm trying to update m4 on Solaris. All seems to work nicely with the
exception of 198.sysval test. The tests do show:

...
Checking /builds/vmarek/autoconf/components/m4/m4-1.4.19/checks/198.sysval                                                                                                                                         
@ ../doc/m4.texi:6751: Origin of test                                                                                                                                                                              
/builds/vmarek/autoconf/components/m4/m4-1.4.19/checks/198.sysval: stderr mismatch                                                                                                                                 
--- m4-tmp.9274/m4-xerr 2025-04-18 17:08:31.490034716 +0200                                                                                                                                                        
+++ m4-tmp.9274/m4-err  2025-04-18 17:08:31.472374843 +0200                                                                                                                                                        
@@ -0,0 +1 @@                                                                                                                                                                                                      
+sh: 12103 Killed                                                                                                                                                                                                  
...

I believe that it is the unexpected string on stderr which trips the
test. I can reproduce it manually by running

(solaris)$ sh -c "/bin/sh -c 'kill -9 \$\$'; st=\$?; test \$st = 137 || test \$st = 265"
sh: 10677: Killed

When I try on Linux I get:
$ sh -c "/bin/sh -c 'kill -9 \$\$'; st=\$?; test \$st = 137 || test \$st = 265"
Killed

So I thought that maybe it is unexpected PID in the output but I was not
able to find a code handling "Killed" on it's own.

I have tried to modify the test to redirect stderr to /dev/null in
various ways, but was also unsuccessful. 

For the moment I have just commented out the test. I'm sorry I don't
have better solution. I would be more than happy help testing any
patches.

Thanks for M4!
-- 
	Vlad