Index: src/libcfa/concurrency/kernel.c
===================================================================
--- src/libcfa/concurrency/kernel.c	(revision 551002701de3f5da95cdd4a5929fc09d3f4b03bc)
+++ src/libcfa/concurrency/kernel.c	(revision 214e8da33e6cb23acc53448d1c57eea90c6f03ae)
@@ -16,4 +16,5 @@
 //C Includes
 #include <stddef.h>
+#include <errno.h>
 extern "C" {
 #include <stdio.h>