Correction: I misread the code in os_unix.c. There is NO simplistic mutex mechanism, just the pthread_mutex_lock call. So, the only way for your code to fail because of this would be to
1. compile without THREADSAFE And 2. disable asserts. I don't know how this is done in C, but I assume that in a release build, asserts are off. Also, it would, of course, fail, if the pthread_mutex_lock call does not work properly..
