[C++] Fix if_recipe.mk
diff --git a/eval.cc b/eval.cc
index de49297..ccbcf77 100644
--- a/eval.cc
+++ b/eval.cc
@@ -169,7 +169,6 @@
 
 void Evaluator::EvalIf(const IfAST* ast) {
   loc_ = ast->loc();
-  last_rule_ = NULL;
 
   bool is_true;
   switch (ast->op) {