Index: libcfa/src/concurrency/io/setup.cfa
===================================================================
--- libcfa/src/concurrency/io/setup.cfa	(revision a76efc81ae8d3521f1f24b43e72a0493a1b8600c)
+++ libcfa/src/concurrency/io/setup.cfa	(revision 43784ac7ca1579ca19d7dc8bc4e1423986fd4d97)
@@ -15,5 +15,5 @@
 
 #define __cforall_thread__
-#define _GNU_SOURCE         /* See feature_test_macros(7) */
+#define _GNU_SOURCE
 
 #if defined(__CFA_DEBUG__)