[Zope] compile python on openbsd

Hello: I have read the install.txt in the zope.src for the current release. It says I must use libpthread for my python compile. Where do I find this file. Once I get the library, when I cimpile python; I assume I use the use-lib = path or something like that. I cant find any docs on the web that tell me how to find this library. I've seen references to libpthread.so . But not much in english. cj