Index: gap-4r6p5/src/system.c
===================================================================
--- gap-4r6p5.orig/src/system.c	2013-07-20 21:02:26.000000000 +0200
+++ gap-4r6p5/src/system.c	2013-09-11 22:17:17.000000000 +0200
@@ -1326,7 +1326,7 @@
 
 #include <mach/mach.h>
 
-#if defined(SYS_IS_DARWIN) && SYS_IS_DARWIN
+#if (defined(SYS_IS_DARWIN) && SYS_IS_DARWIN) || defined(__gnu_hurd__)
 #define task_self mach_task_self
 #endif
 
