Backport into build-201102032246-5.1.52sp1

> ------------------------------------------------------------
> revno: 3496.1.39
> revision-id: jon.hauglid@oracle.com-20101019081957-zf2ohl7wgnhvnnb0
> parent: tor.didriksen@oracle.com-20101019070648-jhi9ezq3b5qk4wcm
> committer: Jon Olav Hauglid <jon.hauglid@oracle.com>
> branch nick: mysql-5.1-bugteam-bug57274
> timestamp: Tue 2010-10-19 10:19:57 +0200
> message:
>   Bug #57274 SET GLOBAL debug crashes on Solaris in embedded server mode
>              (variables_debug fails)
>   
>   The problem was that "SET GLOBAL debug" could cause a crash on Solaris.
>   The crash happened if the server failed to open the trace file given in 
>   the "SET GLOBAL debug" statement. This caused an error message to be
>   printed to stderr containing the process name. However, printing to
>   stderr crashed the server since the pointer to the process name had
>   not been initialized.
>   
>   This patch fixes the problem by initializing the process name 
>   properly when doing "SET GLOBAL debug".
>   
>   No test case added as this bug was repeatable with existing test
>   coverage in variables_debug.test.

dbug/dbug.c

@@ -744,6 +744,7 @@ void _db_set_init_(const char *control)
   CODE_STATE tmp_cs;
   bzero((uchar*) &tmp_cs, sizeof(tmp_cs));
   tmp_cs.stack= &init_settings;
+  tmp_cs.process= db_process ? db_process : "dbug";
   DbugParse(&tmp_cs, control);
 }