Update Makefile

diff --git a/ast b/ast
index 19979ef8587bc8ce9f49a0c470ef0c8c53756003..c5ee17c59538709a7be39201461e7e1ba12acd37 160000 (submodule)
--- a/ast
+++ b/ast
@@ -1 +1 @@
-Subproject commit 19979ef8587bc8ce9f49a0c470ef0c8c53756003
+Subproject commit c5ee17c59538709a7be39201461e7e1ba12acd37