THRIFT-3360 Improve cross test servers and clients further

This closes #629
diff --git a/test/hs/Makefile.am b/test/hs/Makefile.am
index e171248..b41a391 100644
--- a/test/hs/Makefile.am
+++ b/test/hs/Makefile.am
@@ -39,3 +39,5 @@
 all-local: stubs
 	ghc -igen-hs TestServer.hs
 	ghc -igen-hs TestClient.hs
+
+precross: all-local