pthread weak symbols

[Matt Turner]

I'm interested in avoiding pthread/locking overhead in Mesa
(http://mesa3d.org/) when the application is not using threads.

I've read about glibc's weak pthread symbols that are intended to
solve this problem, but I've also read on this list that they weren't
a good idea and have some (unknown to me) problems.

Can I get some clarification about what problems there are with the
weak pthread symbols, and perhaps some suggested alternative
solutions?