make: Added -fno-strict-overflow to makefile

modified CFLAGS to avoid gcc optimising the signed integer overflow checks.

CRs-Fixed: 691916.
Change-Id: I9c01609eaa486351f79289e4df803b9281c65dff
diff --git a/makefile b/makefile
index 40cb9f0..0cf7e7c 100644
--- a/makefile
+++ b/makefile
@@ -63,6 +63,7 @@
 # setup toolchain prefix
 TOOLCHAIN_PREFIX ?= arm-eabi-
 CFLAGS += -fstack-protector-all
+CFLAGS += -fno-strict-overflow
 CPPFLAGS := -fno-exceptions -fno-rtti -fno-threadsafe-statics
 #CPPFLAGS += -Weffc++
 ASMFLAGS := -DASSEMBLY