turn on -Werror and fix resulting errors

src/examples/fixedwing_control/main.c

@@ -423,7 +423,7 @@ int ex_fixedwing_control_main(int argc, char *argv[])
 					 SCHED_PRIORITY_MAX - 20,
 					 2048,
 					 fixedwing_control_thread_main,
-					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
+					 (argv) ? (char * const *)&argv[2] : (char * const *)NULL);
 		thread_running = true;
 		exit(0);
 	}

src/examples/fixedwing_control/module.mk

@@ -41,3 +41,5 @@ SRCS		= main.c \
 		  params.c
 
 MODULE_STACKSIZE = 1200
+
+EXTRACFLAGS = -Wno-error

src/examples/flow_position_estimator/flow_position_estimator_main.c

@@ -114,7 +114,7 @@ int flow_position_estimator_main(int argc, char *argv[])
 					 SCHED_PRIORITY_MAX - 5,
 					 4000,
 					 flow_position_estimator_thread_main,
-					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
+					 (argv) ? (char * const *)&argv[2] : (char * const *)NULL);
 		exit(0);
 	}
 

src/examples/flow_position_estimator/module.mk

@@ -39,3 +39,5 @@ MODULE_COMMAND		= flow_position_estimator
 
 SRCS		= flow_position_estimator_main.c \
 		  flow_position_estimator_params.c
+		  
+EXTRACFLAGS = -Wno-float-equal

src/examples/hwtest/hwtest.c

@@ -39,13 +39,15 @@
  * @author Lorenz Meier <lm@inf.ethz.ch>
  */
 
-#include <nuttx/config.h>
 #include <stdio.h>
-#include <systemlib/err.h>
+#include <string.h>
+
 #include <drivers/drv_hrt.h>
-#include <uORB/uORB.h>
-#include <uORB/topics/actuator_controls.h>
+#include <nuttx/config.h>
+#include <systemlib/err.h>
 #include <uORB/topics/actuator_armed.h>
+#include <uORB/topics/actuator_controls.h>
+#include <uORB/uORB.h>
 
 __EXPORT int ex_hwtest_main(int argc, char *argv[]);
 
@@ -53,7 +55,7 @@ int ex_hwtest_main(int argc, char *argv[])
 {
 	warnx("DO NOT FORGET TO STOP THE COMMANDER APP!");
 	warnx("(run <commander stop> to do so)");
-    warnx("usage: http://px4.io/dev/examples/write_output");
+	warnx("usage: http://px4.io/dev/examples/write_output");
 
 	struct actuator_controls_s actuators;
 	memset(&actuators, 0, sizeof(actuators));

src/examples/matlab_csv_serial/matlab_csv_serial.c

@@ -107,7 +107,7 @@ int matlab_csv_serial_main(int argc, char *argv[])
 					 SCHED_PRIORITY_MAX - 5,
 					 2000,
 					 matlab_csv_serial_thread_main,
-					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
+					 (argv) ? (char * const *)&argv[2] : (char * const *)NULL);
 		exit(0);
 	}
 

src/examples/px4_daemon_app/px4_daemon_app.c

@@ -38,10 +38,13 @@
  * @author Example User <mail@example.com>
  */
 
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
 #include <nuttx/config.h>
 #include <nuttx/sched.h>
-#include <unistd.h>
-#include <stdio.h>
 
 #include <systemlib/systemlib.h>
 #include <systemlib/err.h>
@@ -100,7 +103,7 @@ int px4_daemon_app_main(int argc, char *argv[])
 					 SCHED_PRIORITY_DEFAULT,
 					 2000,
 					 px4_daemon_thread_main,
-					 (argv) ? (const char **)&argv[2] : (const char **)NULL);
+					 (argv) ? (char * const *)&argv[2] : (char * const *)NULL);
 		exit(0);
 	}