Merge pull request #539 from schwa423/linux_global_lock

Use pthread_mutex for global lock on Linux.

glslang/OSDependent/Unix/ossource.cpp

@@ -165,11 +165,29 @@ bool OS_FreeTLSIndex(OS_TLSIndex nIndex)
 		return false;
 }
 
-// TODO: non-windows: if we need these on linux, flesh them out
-void InitGlobalLock() { }
-void GetGlobalLock() { }
-void ReleaseGlobalLock() { }
+namespace {
+pthread_mutex_t gMutex;
+}
+
+void InitGlobalLock()
+{
+  pthread_mutexattr_t mutexattr;
+  pthread_mutexattr_init(&mutexattr);
+  pthread_mutexattr_settype(&mutexattr, PTHREAD_MUTEX_RECURSIVE);
+  pthread_mutex_init(&gMutex, &mutexattr);
+}
+
+void GetGlobalLock()
+{
+  pthread_mutex_lock(&gMutex);
+}
+
+void ReleaseGlobalLock()
+{
+  pthread_mutex_unlock(&gMutex);
+}
 
+// TODO: non-windows: if we need these on linux, flesh them out
 void* OS_CreateThread(TThreadEntrypoint /*entry*/)
 {
     return 0;