Index: kernel/generic/include/ipc/ipc.h
===================================================================
--- kernel/generic/include/ipc/ipc.h	(revision 12ab886ceb37e8c6e90160bc20c1d059e2da09fb)
+++ kernel/generic/include/ipc/ipc.h	(revision 2b17f47a12be0ade0b8cfd4a26a738c33c7d2336)
@@ -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;