Index: kernel/generic/include/synch/spinlock.h
===================================================================
--- kernel/generic/include/synch/spinlock.h	(revision b3f8fb771f871e7f2bb35ce9339717639e8f86d6)
+++ kernel/generic/include/synch/spinlock.h	(revision c27c988cab02c1a8170e26cd226fd6f2d264a3d1)
@@ -54,4 +54,5 @@
  */
 #define SPINLOCK_DECLARE(slname) 	spinlock_t slname
+#define SPINLOCK_EXTERN(slname)		extern spinlock_t slname
 
 /*
@@ -103,8 +104,7 @@
 #else
 
-typedef void spinlock_t;
-
 /* On UP systems, spinlocks are effectively left out. */
 #define SPINLOCK_DECLARE(name)
+#define SPINLOCK_EXTERN(name)
 #define SPINLOCK_INITIALIZE(name)