Index: libcfa/src/concurrency/kernel/cluster.cfa
===================================================================
--- libcfa/src/concurrency/kernel/cluster.cfa	(revision 33b7d490d37c1f84e96a85cdf1c8baad2b08aeb8)
+++ libcfa/src/concurrency/kernel/cluster.cfa	(revision 48a91e270c570a6f6635a022d7dfafbbd208229b)
@@ -16,4 +16,5 @@
 
 #define __cforall_thread__
+#define _GNU_SOURCE
 
 #include "bits/defs.hfa"