THRIFT-4717: fix up make clean with autoconf
diff --git a/test/hs/Makefile.am b/test/hs/Makefile.am
index 1748906..817070d 100644
--- a/test/hs/Makefile.am
+++ b/test/hs/Makefile.am
@@ -30,9 +30,18 @@
 	sh run-test.sh Include
 
 clean-local:
-	$(RM) -r gen-hs
+	$(RM) -r gen-hs/
 	$(RM) *.hi
 	$(RM) *.o
+	$(RM) TestClient
+	$(RM) TestServer
+
+dist-hook:
+	$(RM) -r $(distdir)/gen-hs/
+	$(RM) $(distdir)/*.hi
+	$(RM) $(distdir)/*.o
+	$(RM) $(destdir)/TestClient
+	$(RM) $(destdir)/TestServer
 
 all-local: stubs
 	ghc -igen-hs TestServer.hs