Copter: add option to disable LOITER 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_LOITER_ENABLED   DISABLED            // disable loiter mode support
 //#define MODE_POSHOLD_ENABLED  DISABLED            // disable poshold mode support
 //#define MODE_SMARTRTL_ENABLED DISABLED            // disable smartrtl mode support
 

ArduCopter/Copter.h

@@ -968,7 +968,9 @@ private:
     ModeFlip mode_flip;
     ModeGuided mode_guided;
     ModeLand mode_land;
+#if MODE_LOITER_ENABLED == ENABLED
     ModeLoiter mode_loiter;
+#endif
 #if MODE_POSHOLD_ENABLED == ENABLED
     ModePosHold mode_poshold;
 #endif

ArduCopter/config.h

@@ -273,6 +273,12 @@
 # define MODE_AUTO_ENABLED ENABLED
 #endif
 
+//////////////////////////////////////////////////////////////////////////////
+// Loiter mode - allows vehicle to hold global position
+#ifndef MODE_LOITER_ENABLED
+# define MODE_LOITER_ENABLED ENABLED
+#endif
+
 //////////////////////////////////////////////////////////////////////////////
 // Position Hold - enable holding of global position
 #ifndef MODE_POSHOLD_ENABLED

ArduCopter/mode.cpp

@@ -60,9 +60,11 @@ Copter::Mode *Copter::mode_from_mode_num(const uint8_t mode)
             ret = &mode_circle;
             break;
 
+#if MODE_LOITER_ENABLED == ENABLED
         case LOITER:
             ret = &mode_loiter;
             break;
+#endif
 
         case GUIDED:
             ret = &mode_guided;

ArduCopter/switches.cpp

@@ -569,7 +569,7 @@ void Copter::do_aux_switch_function(int8_t ch_function, uint8_t ch_flag)
             break;
 
         case AUXSW_PRECISION_LOITER:
-#if PRECISION_LANDING == ENABLED
+#if PRECISION_LANDING == ENABLED && MODE_LOITER_ENABLED == ENABLED
             switch (ch_flag) {
                 case AUX_SWITCH_HIGH:
                     mode_loiter.set_precision_loiter_enabled(true);