message: Specify the optimization level in a variable.
  Make it possible to specify the optimization level from the command
  line and make it the same regardless of the BUILD_TYPE.
diff: @@ -88,15 +88,16 @@ ARFLAGS := -r
  TARGET_TOOLCHAIN_PREFIX :=
  TARGET_TOOLCHAIN_ROOT :=
  +OPTIMIZATION_LEVEL := -O3
  ifeq ($(BUILD_TYPE), debug)
  - CXXFLAGS += -DDEBUG -g
  - CCFLAGS += -DDEBUG -g
  + CXXFLAGS += -DDEBUG -g $(OPTIMIZATION_LEVEL)
  + CCFLAGS += -DDEBUG -g $(OPTIMIZATION_LEVEL)
  else ifeq ($(BUILD_TYPE), release)
  - CXXFLAGS += -DNDEBUG -O3 -DTF_LITE_STRIP_ERROR_STRINGS
  - CCFLAGS += -DNDEBUG -O3 -DTF_LITE_STRIP_ERROR_STRINGS
  + CXXFLAGS += -DNDEBUG $(OPTIMIZATION_LEVEL) -DTF_LITE_STRIP_ERROR_STRINGS
  + CCFLAGS += -DNDEBUG $(OPTIMIZATION_LEVEL) -DTF_LITE_STRIP_ERROR_STRINGS
  else
  - CXXFLAGS += -DNDEBUG -O3
  - CCFLAGS += -DNDEBUG -O3
  + CXXFLAGS += -DNDEBUG $(OPTIMIZATION_LEVEL)
  + CCFLAGS += -DNDEBUG $(OPTIMIZATION_LEVEL)
  endif
  # This library is the main target for this makefile. It will contain a minimal
  