diff --git a/libgcc/config/gthr-vxworks-thread.c b/libgcc/config/gthr-vxworks-thread.c
index 8e26d855931..a723005e03b 100644
--- a/libgcc/config/gthr-vxworks-thread.c
+++ b/libgcc/config/gthr-vxworks-thread.c
@@ -27,6 +27,8 @@ see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
    exposed by gthr-vxworks.h, using APIs exposed by regular (!AE/653)
    VxWorks kernels.  */
 
+#if __GTHREAD_CXX0X
+
 #include "gthr.h"
 #include <taskLib.h>
 #include <stdlib.h>
@@ -384,3 +386,5 @@ __gthread_detach (__gthread_t __threadid)
 
   return OK;
 }
+
+#endif
diff --git a/libgcc/config/gthr-vxworks.h b/libgcc/config/gthr-vxworks.h
index d49809a9c2c..beedf5ee713 100644
--- a/libgcc/config/gthr-vxworks.h
+++ b/libgcc/config/gthr-vxworks.h
@@ -267,7 +267,7 @@ extern int __gthread_cond_wait_recursive (__gthread_cond_t *cond,
 /* We do not support C++0x threads on that VxWorks 653, which we can
    recognize by VTHREADS being defined.  */
 
-#ifndef VTHREADS
+#if _VXWORKS_MAJOR_GE(6) && !defined(VTHREADS)
 
 #define __GTHREADS_CXX0X 1
 
@@ -330,7 +330,7 @@ extern int __gthread_detach (__gthread_t thread);
 
 extern __gthread_t __gthread_self (void);
 
-#endif
+#endif /* _VXWORKS_MAJOR_GE(6) && !defined(VTHREADS) */
 
 #ifdef __cplusplus
 }