+/* If _NEXT_SOURCE is defined, certain header files make more
+ * constants visible to us.
+ * Perhaps it would have been wise, also to define NON_POSIX_SOURCE.
+ * Things seemed to work better without it however, so I have not
+ * done it. Nevertheless we do the signal stuff in a NON_POSIX way,
+ * see StgMacros.lh.
+ * CaS
+ */
+#ifdef nextstep3_TARGET_OS
+#define _NEXT_SOURCE
+#endif
+
+#ifdef aix_TARGET_OS
+/* for fd_set */
+#include <sys/select.h>
+#endif
+