Re-enable threaded builds. Need to protect usage of mutex->m_*

variables to only use them a) when debugging, and b) when we don't
have real thread support.

This commit was SVN r15099.

opal/threads/mutex.c

@@ -77,7 +77,7 @@ static void opal_mutex_construct(opal_mutex_t *m)
     mutex_init(&m->m_lock_solaris, USYNC_THREAD, NULL);
 #endif
 
-#if OMPI_ENABLE_DEBUG
+#if OMPI_ENABLE_DEBUG && !OMPI_HAVE_THREAD_SUPPORT
     m->m_lock_debug = 0;
     m->m_lock_file = NULL;
     m->m_lock_line = 0;