Jack Jansen: The GUSI 2.0 I/O library (which is used on the Mac)
doesn't use the special header file for select anymore.
diff --git a/Include/myselect.h b/Include/myselect.h
index 1b3a834..fe6cbdc 100644
--- a/Include/myselect.h
+++ b/Include/myselect.h
@@ -51,7 +51,7 @@
 
 #else /* !HAVE_SYS_SELECT_H */
 
-#ifdef USE_GUSI
+#ifdef USE_GUSI1
 /* If we don't have sys/select the definition may be in unistd.h */
 #include <GUSI.h>
 #endif