turn on -Werror and fix resulting errors

src/drivers/ardrone_interface/ardrone_interface.c

@@ -121,7 +121,7 @@ int ardrone_interface_main(int argc, char *argv[])
 						    SCHED_PRIORITY_MAX - 15,
 						    1100,
 						    ardrone_interface_thread_main,
-						    (argv) ? (const char **)&argv[2] : (const char **)NULL);
+						    (argv) ? (char * const *)&argv[2] : (char * const *)NULL);
 		exit(0);
 	}
 

src/drivers/boards/aerocore/aerocore_led.c

@@ -45,6 +45,7 @@
 #include "board_config.h"
 
 #include <arch/board/board.h>
+#include <systemlib/err.h>
 
 /*
  * Ideally we'd be able to get these from up_internal.h,
@@ -54,7 +55,7 @@
  * CONFIG_ARCH_LEDS configuration switch.
  */
 __BEGIN_DECLS
-extern void led_init();
+extern void led_init(void);
 extern void led_on(int led);
 extern void led_off(int led);
 extern void led_toggle(int led);

src/drivers/frsky_telemetry/frsky_telemetry.c

@@ -221,7 +221,7 @@ int frsky_telemetry_main(int argc, char *argv[])
 					  SCHED_PRIORITY_DEFAULT,
 					  2000,
 					  frsky_telemetry_thread_main,
-					  (const char **)argv);
+					  (char * const *)argv);
 
 		while (!thread_running) {
 			usleep(200);

src/drivers/hott/hott_sensors/hott_sensors.cpp

@@ -214,7 +214,7 @@ hott_sensors_main(int argc, char *argv[])
 					     SCHED_PRIORITY_DEFAULT,
 					     1024,
 					     hott_sensors_thread_main,
-					     (argv) ? (const char **)&argv[2] : (const char **)NULL);
+					     (argv) ? (char * const *)&argv[2] : (char * const *)NULL);
 		exit(0);
 	}
 

src/drivers/hott/hott_telemetry/hott_telemetry.cpp

@@ -240,7 +240,7 @@ hott_telemetry_main(int argc, char *argv[])
 					 SCHED_PRIORITY_DEFAULT,
 					 2048,
 					 hott_telemetry_thread_main,
-					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
+					 (argv) ? (char * const *)&argv[2] : (char * const *)NULL);
 		exit(0);
 	}
 

src/drivers/px4flow/module.mk

@@ -40,3 +40,5 @@ MODULE_COMMAND	= px4flow
 SRCS		= px4flow.cpp
 
 MAXOPTIMIZATION	 = -Os
+
+EXTRACXXFLAGS = -Wno-attributes

src/drivers/px4flow/px4flow.cpp

@@ -106,7 +106,7 @@ struct i2c_frame {
 };
 struct i2c_frame f;
 
-typedef struct i2c_integral_frame {
+struct i2c_integral_frame {
 	uint16_t frame_count_since_last_readout;
 	int16_t pixel_flow_x_integral;
 	int16_t pixel_flow_y_integral;

src/drivers/roboclaw/roboclaw_main.cpp

@@ -109,7 +109,7 @@ int roboclaw_main(int argc, char *argv[])
 					 SCHED_PRIORITY_MAX - 10,
 					 2048,
 					 roboclaw_thread_main,
-					 (const char **)argv);
+					 (char * const *)argv);
 		exit(0);
 
 	} else if (!strcmp(argv[1], "test")) {

src/drivers/trone/trone.cpp

@@ -206,7 +206,7 @@ static const uint8_t crc_table[] = {
     0xfa, 0xfd, 0xf4, 0xf3
 };
 
-uint8_t crc8(uint8_t *p, uint8_t len){
+static uint8_t crc8(uint8_t *p, uint8_t len) {
         uint16_t i;
         uint16_t crc = 0x0;