Attempt to fix the FreeBSD build, disable multiprocessing

Speculative quick fix based on clang-X86_64-freebsd output:

  File "/usr/local/lib/python2.6/multiprocessing/synchronize.py", line 33, in <module>
    " function, see issue 3770.")
ImportError: This platform lacks a functioning sem_open implementation, therefore, the required synchronization primitives needed will not function, see issue 3770.

llvm-svn: 193457

llvm/utils/lit/lit/main.py

@@ -111,7 +111,8 @@ def write_test_results(run, lit_config, testing_time, output_path):
 def main(builtinParameters = {}):
     # Use processes by default on Unix platforms.
     isWindows = platform.system() == 'Windows'
-    useProcessesIsDefault = (not isWindows) and platform.system() != 'OpenBSD'
+    # multiprocessing is broken on various BSD Python versions: http://bugs.python.org/issue3770
+    useProcessesIsDefault = (not isWindows) and ('BSD' not in platform.system())
 
     global options
     from optparse import OptionParser, OptionGroup