weak implementation of threads has problems - kse fix attached

[Dan Nelson]

In the last episode (Jun 08), Joe Marcus Clarke said:
> If we switched PTHREAD_LIBS to -pthread, we wouldn't need this.  Shared
> objects would not have a link to libpthread, and shared objects that
> really referenced pthread symbols would still require executables to be
> linked to PTHREAD_LIBS (i.e. how it works on 4.X).

It'd still be a good sanity check for people porting libraries, I
think.

-- 
	Dan Nelson
	dnelson at allantgroup.com