[patch] Allow for libc containing libpthread in testsuite.

[Joel Brobecker]

> I will check this in in a few days if there are no objections.
> 
> 2010-03-01  Doug Evans  <dje@google.com>
> 
> 	* lib/gdb.exp (gdb_compile_pthreads): Handle case where
> 	libc contains libpthread.

I think this is fine. Given the modest number of tests that involve
threading, and their overal size, I don't think an extra link will
slow the testsuite down noticeably...

-- 
Joel