From 0ddeb56a058ba10624ce9d73c69cc158039138b3 Mon Sep 17 00:00:00 2001
From: Peter Barker <pbarker@barker.dropbear.id.au>
Date: Fri, 23 Feb 2018 14:55:51 +1100
Subject: [PATCH] Copter: add option to disable DRIFT flight mode

Saves about 1kB of space
---
 ArduCopter/APM_Config.h | 1 +
 ArduCopter/Copter.h     | 2 ++
 ArduCopter/config.h     | 6 ++++++
 ArduCopter/mode.cpp     | 2 ++
 4 files changed, 11 insertions(+)

diff --git a/ArduCopter/APM_Config.h b/ArduCopter/APM_Config.h
index 5765373a68..41f51db89e 100644
--- a/ArduCopter/APM_Config.h
+++ b/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_DRIFT_ENABLED    DISABLED            // disable drift 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
diff --git a/ArduCopter/Copter.h b/ArduCopter/Copter.h
index 8d20372de7..c0d7fd8136 100644
--- a/ArduCopter/Copter.h
+++ b/ArduCopter/Copter.h
@@ -964,7 +964,9 @@ private:
 #endif
     ModeBrake mode_brake;
     ModeCircle mode_circle;
+#if MODE_DRIFT_ENABLED == ENABLED
     ModeDrift mode_drift;
+#endif
     ModeFlip mode_flip;
     ModeGuided mode_guided;
     ModeLand mode_land;
diff --git a/ArduCopter/config.h b/ArduCopter/config.h
index 509d5786d4..299076e6c9 100644
--- a/ArduCopter/config.h
+++ b/ArduCopter/config.h
@@ -273,6 +273,12 @@
 # define MODE_AUTO_ENABLED ENABLED
 #endif
 
+//////////////////////////////////////////////////////////////////////////////
+// Drift - fly vehicle in altitude-held, coordinated-turn mode
+#ifndef MODE_DRIFT_ENABLED
+# define MODE_DRIFT_ENABLED ENABLED
+#endif
+
 //////////////////////////////////////////////////////////////////////////////
 // Loiter mode - allows vehicle to hold global position
 #ifndef MODE_LOITER_ENABLED
diff --git a/ArduCopter/mode.cpp b/ArduCopter/mode.cpp
index 4d4ec6a86a..c9b8896f8d 100644
--- a/ArduCopter/mode.cpp
+++ b/ArduCopter/mode.cpp
@@ -78,9 +78,11 @@ Copter::Mode *Copter::mode_from_mode_num(const uint8_t mode)
             ret = &mode_rtl;
             break;
 
+#if MODE_DRIFT_ENABLED == ENABLED
         case DRIFT:
             ret = &mode_drift;
             break;
+#endif
 
 #if MODE_SPORT_ENABLED == ENABLED
         case SPORT: