diff --git a/src/BulletMultiThreaded/PosixThreadSupport.cpp b/src/BulletMultiThreaded/PosixThreadSupport.cpp
index 39d0be058..ffde13d89 100644
--- a/src/BulletMultiThreaded/PosixThreadSupport.cpp
+++ b/src/BulletMultiThreaded/PosixThreadSupport.cpp
@@ -43,7 +43,9 @@ PosixThreadSupport::~PosixThreadSupport()
 	stopSPU();
 }
 
+#if (defined (__APPLE__))
 #define NAMED_SEMAPHORES
+#endif
 
 // this semaphore will signal, if and how many threads are finished with their work
 static sem_t* mainSemaphore;