Made SIMULATOR_BUILD a makefile driven option.

make/source.mk

@@ -182,6 +182,10 @@ else
 COMMON_SRC := $(COMMON_SRC) $(FC_SRC) $(COMMON_DEVICE_SRC)
 endif
 
+ifeq ($(SIMULATOR_BUILD),yes)
+TARGET_FLAGS := -DSIMULATOR_BUILD $(TARGET_FLAGS)
+endif
+
 SPEED_OPTIMISED_SRC := ""
 SIZE_OPTIMISED_SRC  := ""
 

make/targets.mk

@@ -182,6 +182,7 @@ TARGET_MCU := STM32F7
 
 else ifeq ($(TARGET),$(filter $(TARGET), $(SITL_TARGETS)))
 TARGET_MCU := SITL
+SIMULATOR_BUILD = yes
 
 else ifeq ($(TARGET),$(filter $(TARGET), $(F1_TARGETS)))
 TARGET_MCU := STM32F1

src/main/target/SITL/target.h

@@ -29,7 +29,6 @@
 
 #define TARGET_BOARD_IDENTIFIER "SITL"
 
-#define SIMULATOR_BUILD
 #define SIMULATOR_MULTITHREAD
 
 // use simulatior's attitude directly