Allow building a simplified libsir without any pthread dependency, which would be useful for embedded use, platforms without pthreads, or for static linking and avoiding the pthreads dependency for applications that don't or and won't require threads.
Allow building a simplified libsir without any pthread dependency, which would be useful for embedded use, platforms without pthreads, or for static linking and avoiding the pthreads dependency for applications that don't or and won't require threads.