Patch by Michael Pruett: make regen work on Irix 6.0 and 6.5.
diff --git a/Lib/plat-irix6/regen b/Lib/plat-irix6/regen
index c950a47..6a2cb40 100755
--- a/Lib/plat-irix6/regen
+++ b/Lib/plat-irix6/regen
@@ -1,6 +1,7 @@
 #! /bin/sh
 case `uname -sr` in
-'IRIX '[45].*)	;;
+'IRIX '[456].*)	;;
+'IRIX64 '[456].*)	;;
 *)	echo Probably not on an IRIX system 1>&2
 	exit 1;;
 esac