[Patch] Fix testsuite_shared.cc vs --enable-threads=single

[Benjamin Kosnik]

Thanks. Looks good. I think I only tested with --enable-shared with this...

> 2006-05-22  Paolo Carlini  <pcarlini@suse.de>
> 
> 	* testsuite/testsuite_shared.cc: Fix --enable-threads=single build.