http://bugs.winehq.org/show_bug.cgi?id=21896
--- Comment #3 from Matias Colli matiasbsd@gmail.com 2012-05-03 07:10:21 CDT --- OpenBSD has an inferior implementation of pthreads(3).
OpenBSD, like other systems that resemble Unix, provides the pthreads interface for multithreaded programming, which allows one process to run multiple threads at the same time, while the threads share the memory and the open files. The other systems provide kernel threads through pthreads. OpenBSD still provides pthreads through a user-mode library, with no kernel support; so threads above OpenBSD have problems or limitations. The most obvious limitation is that the OpenBSD pthreads library confines all threads of a process to one processor. Another limitation, which seems arbitrary, is that programs using OpenBSD pthreads cannot use sigaltstack(2).