These patches make threading optional in LLVM. The configuration scripts are now
modified to accept a --disable-threads switch. If this is used, the Mutex class
will be implemented with all functions as no-op. Furthermore, linking against
libpthread will not be done. Finally, the ParallelJIT example needs libpthread
so its makefile was changed to always add -lpthread to the link line.
llvm-svn: 23003
Add a Mutex class for thread synchronization in a platform-independent way.
The current implementation only supports pthreads. Win32 use of Critical
Sections will be added later. The design permits other threading models to
be used if (and only if) pthreads is not available.
llvm-svn: 22403
