Use C-style comment
diff --git a/Python/ast.c b/Python/ast.c
index a2b69f5..5d91344 100644
--- a/Python/ast.c
+++ b/Python/ast.c
@@ -1808,7 +1808,7 @@
 
         if (!expr1)
             return NULL;
-        // TODO(jhylton): Figure out why set_context() can't be used here.
+        /* TODO(jhylton): Figure out why set_context() can't be used here. */
         switch (expr1->kind) {
             case GeneratorExp_kind:
                 ast_error(ch, "augmented assignment to generator "