diff --git a/src/s/irix6-0.h b/src/s/irix6-0.h
index be50494c6d7..effe7851b6e 100644
--- a/src/s/irix6-0.h
+++ b/src/s/irix6-0.h
@@ -24,5 +24,8 @@
 
 #undef SA_RESTART
 
+/* It turns out that the #define in irix5-0.h is needed in Irix 6 as well.  */
+#if 0
 /* Canced the #define that is in irix5-0.h.  */
 #undef ospeed
+#endif