From a345842a2d584bbf45f5cc10af3415d5ffc5fa61 Mon Sep 17 00:00:00 2001
From: petevine <petevine@users.noreply.github.com>
Date: Fri, 6 May 2016 10:06:06 +0200
Subject: [PATCH] Update main.mk

---
 mk/main.mk | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mk/main.mk b/mk/main.mk
index 493b61051331f..fd3e3d0216772 100644
--- a/mk/main.mk
+++ b/mk/main.mk
@@ -131,7 +131,7 @@ ifdef CFG_DISABLE_OPTIMIZE
   CFG_JEMALLOC_FLAGS += --enable-debug
 else
   # The rtopt cfg turns off runtime sanity checks
-  CFG_RUSTC_FLAGS += -O --cfg rtopt
+  CFG_RUSTC_FLAGS += -C opt-level=2 --cfg rtopt
 endif
 
 CFG_JEMALLOC_FLAGS += $(JEMALLOC_FLAGS)