SITL: rename simin to rcin for better readability

libraries/AP_HAL_SITL/SITL_State.cpp

@@ -116,7 +116,7 @@ void SITL_State::_sitl_setup(const char *home_str)
  */
 void SITL_State::_setup_fdm(void)
 {
-    if (!_sitl_rc_in.bind("0.0.0.0", _simin_port)) {
+    if (!_sitl_rc_in.bind("0.0.0.0", _rcin_port)) {
         fprintf(stderr, "SITL: socket bind failed - %s\n", strerror(errno));
         exit(1);
     }
@@ -198,9 +198,9 @@ void SITL_State::wait_clock(uint64_t wait_time_usec)
 
 #ifndef HIL_MODE
 /*
-  check for a SITL FDM packet
+  check for a SITL RC input packet
  */
-void SITL_State::_fdm_input(void)
+void SITL_State::_check_rc_input(void)
 {
     ssize_t size;
     struct pwm_packet {
@@ -271,7 +271,7 @@ void SITL_State::_fdm_input_local(void)
     SITL::Aircraft::sitl_input input;
 
     // check for direct RC input
-    _fdm_input();
+    _check_rc_input();
 
     // construct servos structure for FDM
     _simulator_servos(input);

libraries/AP_HAL_SITL/SITL_State.h

@@ -129,7 +129,7 @@ private:
                      double rollRate, 	double pitchRate,double yawRate,	// Local to plane
                      double xAccel, 	double yAccel, 	double zAccel,		// Local to plane
                      float airspeed,	float altitude);
-    void _fdm_input(void);
+    void _check_rc_input(void);
     void _fdm_input_local(void);
     void _output_to_flightgear(void);
     void _simulator_servos(SITL::Aircraft::sitl_input &input);
@@ -163,7 +163,7 @@ private:
     SocketAPM _sitl_rc_in{true};
     SITL::SITL *_sitl;
     uint16_t _rcout_port;
-    uint16_t _simin_port;
+    uint16_t _rcin_port;
     float _current;
 
     bool _synthetic_clock_mode;

libraries/AP_HAL_SITL/SITL_cmdline.cpp

@@ -129,7 +129,7 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
     _synthetic_clock_mode = false;
     _base_port = 5760;
     _rcout_port = 5502;
-    _simin_port = 5501;
+    _rcin_port = 5501;
     _fdm_address = "127.0.0.1";
     _client_address = nullptr;
     _use_fg_view = false;
@@ -198,7 +198,7 @@ void SITL_State::_parse_command_line(int argc, char * const argv[])
             _instance = atoi(gopt.optarg);
             _base_port  += _instance * 10;
             _rcout_port += _instance * 10;
-            _simin_port += _instance * 10;
+            _rcin_port  += _instance * 10;
         }
         break;
         case 'P':