diff -up uxlaunch-0.56/desktop.c.s390 uxlaunch-0.56/desktop.c
--- uxlaunch-0.56/desktop.c.s390	2010-09-24 21:34:28.000000000 +0200
+++ uxlaunch-0.56/desktop.c	2010-09-24 21:35:14.000000000 +0200
@@ -35,6 +35,8 @@
 #  define __NR_ioprio_set 314
 #elif defined (__powerpc__)
 #  define __NR_ioprio_set 273
+#elif defined (__s390__)
+#  define __NR_ioprio_set 282
 #else
 #  error "Unsupported arch"
 #endif