--- ruby-1.8.6-p36/node.h.ark	2007-06-18 12:02:40.000000000 +0200
+++ ruby-1.8.6-p36/node.h	2007-06-18 12:16:12.000000000 +0200
@@ -17,6 +17,18 @@
 extern "C" {
 #endif
 
+/* sys/ucontext.h uses stack_t, but bits/sigstack.h (which includes the
+ * stack_t definition) is included by signal.h only with BSD_SOURCE
+ * and/or XOPEN_SOURCE >= 500 */
+#ifndef _XOPEN_SOURCE
+#define _XOPEN_SOURCE 500
+#endif
+#ifndef __USE_XOPEN_EXTENDED
+#define __USE_XOPEN_EXTENDED
+#endif
+#include <signal.h>
+
+
 enum node_type {
     NODE_METHOD,
     NODE_FBODY,