diff --git a/src/s/irix5-2.h b/src/s/irix5-2.h
new file mode 100644
index 00000000000..f03746ef07e
--- /dev/null
+++ b/src/s/irix5-2.h
@@ -0,0 +1,5 @@
+#include "irix5-0.h"
+
+/* as of version 5.2, irix no longer uses flock, 
+   according to jackr@wpd.sgi.com.  */
+#undef MAIL_USE_FLOCK