Index: uspace/lib/c/include/async.h
===================================================================
--- uspace/lib/c/include/async.h	(revision 2d78d88c1a4dd5482f60bb59e70d0111398cbbce)
+++ uspace/lib/c/include/async.h	(revision efa3136385a610d2f83fa95aec41b40b7217ccb2)
@@ -350,5 +350,5 @@
  * management. Proper solution needs to be implemented.
  */
-void async_sess_args_set(async_sess_t *sess, iface_t, sysarg_t, sysarg_t);
+extern void async_sess_args_set(async_sess_t *, iface_t, sysarg_t, sysarg_t);
 
 /*