diff --git a/conf/Makefile.stm32 b/conf/Makefile.stm32
index 707d867861..edd19a7e1f 100644
--- a/conf/Makefile.stm32
+++ b/conf/Makefile.stm32
@@ -118,7 +118,7 @@ endif
 MULTILIB = $(shell if $(CC) --print-multi-lib | grep thumb2 > /dev/null ; then echo "yes"; else echo "no"; fi)
 
 CFLAGS = -I. -I./$(ARCH) $(INCLUDES) -D__thumb2__ -Wall -msoft-float -O$(OPT)
-CFLAGS += -Wl,gc-sections
+CFLAGS += -Wl,--gc-sections
 CFLAGS += -mcpu=$(MCU) -mthumb -ansi
 ifeq ("$(MULTILIB)","yes")
 CFLAGS += -mfix-cortex-m3-ldrd
@@ -149,9 +149,9 @@ endif
 AFLAGS += -x assembler-with-cpp -Wa,-adhlns=$(OBJDIR)/$(<:.S=.lst),--g$(DEBUG)
 
 ifeq ("$(MULTILIB)","yes")
-LDFLAGS = -T$(LDSCRIPT) -nostartfiles -O$(OPT) --gc-sections -mthumb -march=armv7 -mfix-cortex-m3-ldrd -msoft-float
+LDFLAGS = -T$(LDSCRIPT) -nostartfiles -O$(OPT) -mthumb -march=armv7 -mfix-cortex-m3-ldrd -msoft-float
 else
-LDFLAGS = -D__thumb2__ -T$(LDSCRIPT) -nostartfiles  -L$(GCC_LIB_DIR) -O$(OPT) --gc-sections
+LDFLAGS = -D__thumb2__ -T$(LDSCRIPT) -nostartfiles  -L$(GCC_LIB_DIR) -O$(OPT)
 endif
 LDFLAGS += -Wl,-Map=$(OBJDIR)/$(TARGET).map,--cref,--gc-sections
 LDLIBS  += -lc -lm -lgcc -lcmsis -lstm32 -l$(LIBOPENCM3_LIB)
diff --git a/sw/airborne/arch/sim/sim_ap.c b/sw/airborne/arch/sim/sim_ap.c
index a37a453baa..c5e1a652db 100644
--- a/sw/airborne/arch/sim/sim_ap.c
+++ b/sw/airborne/arch/sim/sim_ap.c
@@ -17,7 +17,6 @@
 #include "subsystems/nav.h"
 #include "firmwares/fixedwing/stabilization/stabilization_attitude.h"
 #include "firmwares/fixedwing/guidance/guidance_v.h"
-#include "subsystems/sensors/infrared.h"
 #include "commands.h"
 #include "firmwares/fixedwing/main_ap.h"
 #include "ap_downlink.h"
diff --git a/sw/airborne/arch/sim/sim_gps.c b/sw/airborne/arch/sim/sim_gps.c
index 0930c39f34..13ef9b84cd 100644
--- a/sw/airborne/arch/sim/sim_gps.c
+++ b/sw/airborne/arch/sim/sim_gps.c
@@ -47,6 +47,7 @@ value sim_use_gps_pos(value x, value y, value z, value c, value a, value s, valu
   gps.utm_pos.north = Int_val(y);
   gps.utm_pos.zone = Int_val(z);
   lat = lon; /* Just to get rid of the "unused arg" warning */
+  lon = lat; /* Just to get rid of the "unused arg" warning */
 #endif // GPS_USE_LATLONG
 
 
diff --git a/sw/airborne/subsystems/sensors/infrared.h b/sw/airborne/subsystems/sensors/infrared.h
index 4b5e0e4acc..84ad3ac4e3 100644
--- a/sw/airborne/subsystems/sensors/infrared.h
+++ b/sw/airborne/subsystems/sensors/infrared.h
@@ -54,6 +54,10 @@
 */
 #define IR_RollOfIrs(_ir1, _ir2) (_ir1 + _ir2)
 #define IR_PitchOfIrs(_ir1, _ir2) (-(_ir1) + _ir2)
+#else
+#ifndef SITL
+#error "You have to define either HORIZ_SENSOR_ALIGNED or HORIZ_SENSOR_TILTED in the IR section"
+#endif
 #endif
 /* Vertical sensor, TOP_SIGN gives positice values when it's warm on the bottom */
 #ifndef IR_TopOfIr