Add checks for __OpenBSD__.

llvm-svn: 27761
diff --git a/llvm/lib/System/Mutex.cpp b/llvm/lib/System/Mutex.cpp
index 33dff05..abcf77e 100644
--- a/llvm/lib/System/Mutex.cpp
+++ b/llvm/lib/System/Mutex.cpp
@@ -75,7 +75,7 @@
     errorcode = pthread_mutexattr_settype(&attr, kind);
     assert(errorcode == 0);
 
-#ifndef __FreeBSD__
+#if !defined(__FreeBSD__) && !defined(__OpenBSD__)
     // Make it a process local mutex
     errorcode = pthread_mutexattr_setpshared(&attr, PTHREAD_PROCESS_PRIVATE);
 #endif