weak implementation of threads has problems - kse fix attached

[Dan Nelson]

In the last episode (Jun 08), Daniel Eischen said:
> No, I don't want to litter all our thread libraries with strong
> references. As I've said before, build your shared libraries
> correctly so they don't bring in the threads library.

A good addition to bsd.port.mk, right next to the "possible network
server" etc checks, might be to run ldd on all installed shared
libraries and print a warning if any threads libraries show up.  There
are a huge number of ports that install shlibs linked to libpthreads.

-- 
	Dan Nelson
	dnelson at allantgroup.com