casify, cleanup sys

R=r
OCL=22978
CL=22984
diff --git a/test/interface4.go b/test/interface4.go
index 0d72235..a55936d 100644
--- a/test/interface4.go
+++ b/test/interface4.go
@@ -70,6 +70,6 @@
 	nonptrs();
 
 	if bad {
-		sys.exit(1)
+		sys.Exit(1)
 	}
 }