Copter: add option to disable BRAKE flight mode

ArduCopter/APM_Config.h

@@ -24,6 +24,7 @@
 //#define SPRAYER               DISABLED            // disable the crop sprayer feature (two ESC controlled pumps the speed of which depends upon the vehicle's horizontal velocity)
 //#define WINCH_ENABLED         DISABLED            // disable winch support
 //#define MODE_AUTO_ENABLED     DISABLED            // disable auto mode support
+//#define MODE_BRAKE_ENABLED    DISABLED            // disable brake mode support
 //#define MODE_DRIFT_ENABLED    DISABLED            // disable drift mode support
 //#define MODE_GUIDED_ENABLED   DISABLED            // disable guided mode support
 //#define MODE_LOITER_ENABLED   DISABLED            // disable loiter mode support

ArduCopter/Copter.h

@@ -962,7 +962,9 @@ private:
 #if AUTOTUNE_ENABLED == ENABLED
     ModeAutoTune mode_autotune;
 #endif
+#if MODE_BRAKE_ENABLED == ENABLED
     ModeBrake mode_brake;
+#endif
     ModeCircle mode_circle;
 #if MODE_DRIFT_ENABLED == ENABLED
     ModeDrift mode_drift;

ArduCopter/GCS_Mavlink.cpp

@@ -1303,11 +1303,15 @@ void GCS_MAVLINK_Copter::handleMessage(mavlink_message_t* msg)
                     bool shot_mode = (!is_zero(packet.param1) && (copter.control_mode == GUIDED || copter.control_mode == GUIDED_NOGPS));
 
                     if (!shot_mode) {
+#if MODE_BRAKE_ENABLED == ENABLED
                         if (copter.set_mode(BRAKE, MODE_REASON_GCS_COMMAND)) {
                             copter.mode_brake.timeout_to_loiter_ms(2500);
                         } else {
                             copter.set_mode(ALT_HOLD, MODE_REASON_GCS_COMMAND);
                         }
+#else
+                        copter.set_mode(ALT_HOLD, MODE_REASON_GCS_COMMAND);
+#endif
                     } else {
                         // SoloLink is expected to handle pause in shots
                     }

ArduCopter/config.h

@@ -273,6 +273,12 @@
 # define MODE_AUTO_ENABLED ENABLED
 #endif
 
+//////////////////////////////////////////////////////////////////////////////
+// Brake mode - bring vehicle to stop
+#ifndef MODE_BRAKE_ENABLED
+# define MODE_BRAKE_ENABLED ENABLED
+#endif
+
 //////////////////////////////////////////////////////////////////////////////
 // Drift - fly vehicle in altitude-held, coordinated-turn mode
 #ifndef MODE_DRIFT_ENABLED

ArduCopter/mode.cpp

@@ -110,9 +110,11 @@ Copter::Mode *Copter::mode_from_mode_num(const uint8_t mode)
             break;
 #endif
 
+#if MODE_BRAKE_ENABLED == ENABLED
         case BRAKE:
             ret = &mode_brake;
             break;
+#endif
 
         case THROW:
             ret = &mode_throw;