Index: kernel/generic/include/ipc/ipc.h
===================================================================
--- kernel/generic/include/ipc/ipc.h	(revision e1f51712ebecf49aa1054453f57ea2118f705b5f)
+++ kernel/generic/include/ipc/ipc.h	(revision afb1e35bc801349b8b29725021823bbc5542f798)
@@ -206,4 +206,6 @@
 #define IPC_MAX_PHONES  16
 
+#include <synch/spinlock.h>
+#include <synch/mutex.h>
 #include <synch/waitq.h>
 
@@ -226,5 +228,5 @@
 /** Structure identifying phone (in TASK structure) */
 typedef struct {
-	SPINLOCK_DECLARE(lock);
+	mutex_t lock;
 	link_t link;
 	struct answerbox *callee;