Index: libcfa/src/bits/weakso_locks.cfa
===================================================================
--- libcfa/src/bits/weakso_locks.cfa	(revision 780a61412318cddfec5ff2b3146c9767ee2388b4)
+++ libcfa/src/bits/weakso_locks.cfa	(revision 200a2298cdba8448a5f6101cdffaee0b5450c42d)
@@ -25,5 +25,5 @@
 void unlock( blocking_lock & ) {}
 void on_notify( blocking_lock &, struct $thread * ) {}
-size_t on_wait( blocking_lock & ) {}
+size_t on_wait( blocking_lock & ) { return 0; }
 void on_wakeup( blocking_lock &, size_t ) {}
 size_t wait_count( blocking_lock & ) { return 0; }