remove all <cmath> usage

* the NuttX c++ library is incomplete, let's avoid including it until we have a real standard library in place

src/modules/commander/Commander.cpp

@@ -76,7 +76,7 @@
 #include <circuit_breaker/circuit_breaker.h>
 #include <systemlib/mavlink_log.h>
 
-#include <cmath>
+#include <math.h>
 #include <float.h>
 #include <cstring>
 
@@ -768,7 +768,7 @@ Commander::handle_command(vehicle_status_s *status_local, const vehicle_command_
 				bool cmd_arms = (static_cast<int>(cmd.param1 + 0.5f) == 1);
 
 				// Arm/disarm is enforced when param2 is set to a magic number.
-				const bool enforce = (static_cast<int>(std::round(cmd.param2)) == 21196);
+				const bool enforce = (static_cast<int>(roundf(cmd.param2)) == 21196);
 
 				if (!enforce) {
 					if (!land_detector.landed && !is_ground_rover(&status)) {

src/modules/commander/airspeed_calibration.cpp

@@ -48,7 +48,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <poll.h>
-#include <cmath>
+#include <math.h>
 #include <drivers/drv_hrt.h>
 #include <drivers/drv_airspeed.h>
 #include <uORB/topics/differential_pressure.h>

src/modules/commander/gyro_calibration.cpp

@@ -50,7 +50,7 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <poll.h>
-#include <cmath>
+#include <math.h>
 #include <string.h>
 #include <drivers/drv_hrt.h>
 #include <uORB/topics/sensor_combined.h>

src/modules/commander/mag_calibration.cpp

@@ -50,7 +50,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <poll.h>
-#include <cmath>
+#include <math.h>
 #include <fcntl.h>
 #include <drivers/drv_hrt.h>
 #include <drivers/drv_accel.h>