a bunch of thread-safety changes

src/mesa/drivers/x11/xmesaP.h

@@ -1,4 +1,4 @@
-/* $Id: xmesaP.h,v 1.10 2000/05/19 13:08:01 brianp Exp $ */
+/* $Id: xmesaP.h,v 1.11 2000/07/19 23:26:35 brianp Exp $ */
 
 /*
  * Mesa 3-D graphics library
@@ -57,6 +57,9 @@
 #endif
 
 
+extern _glthread_Mutex _xmesa_lock;
+
+
 /* for PF_8R8G8B24 pixel format */
 typedef struct {
    GLubyte b;