Apply fix for M600 filament change

- Patch from #1453 for delta movement plan
- Fix: Set X with code X instead of adding to X

Marlin/Marlin_main.cpp

     #ifdef FILAMENTCHANGEENABLE
     case 600: //Pause for filament change X[pos] Y[pos] Z[relative lift] E[initial retract] L[later retract distance for removal]
     {
-        float target[4];
-        float lastpos[4];
-        target[X_AXIS]=current_position[X_AXIS];
-        target[Y_AXIS]=current_position[Y_AXIS];
-        target[Z_AXIS]=current_position[Z_AXIS];
-        target[E_AXIS]=current_position[E_AXIS];
-        lastpos[X_AXIS]=current_position[X_AXIS];
-        lastpos[Y_AXIS]=current_position[Y_AXIS];
-        lastpos[Z_AXIS]=current_position[Z_AXIS];
-        lastpos[E_AXIS]=current_position[E_AXIS];
+        float target[NUM_AXIS], lastpos[NUM_AXIS], fr60 = feedrate/60;
+        for (int i=0; i<NUM_AXIS; i++)
+          target[i] = lastpos[i] = current_position[i];
+
+        #define BASICPLAN plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], fr60, active_extruder);
+        #ifdef DELTA
+          #define RUNPLAN calculate_delta(target); BASICPLAN
+        #else
+          #define RUNPLAN BASICPLAN
+        #endif
+
         //retract by E
         if(code_seen('E'))
         {
             target[E_AXIS]+= FILAMENTCHANGE_FIRSTRETRACT ;
           #endif
         }
-        plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], feedrate/60, active_extruder);
+        RUNPLAN;
 
         //lift Z
         if(code_seen('Z'))
             target[Z_AXIS]+= FILAMENTCHANGE_ZADD ;
           #endif
         }
-        plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], feedrate/60, active_extruder);
+        RUNPLAN;
 
         //move xy
         if(code_seen('X'))
         {
-          target[X_AXIS]+= code_value();
+          target[X_AXIS]= code_value();
         }
         else
         {
           #endif
         }
 
-        plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], feedrate/60, active_extruder);
+        RUNPLAN;
 
         if(code_seen('L'))
         {
           #endif
         }
 
-        plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], feedrate/60, active_extruder);
+        RUNPLAN;
 
         //finish moves
         st_synchronize();
         }
         current_position[E_AXIS]=target[E_AXIS]; //the long retract of L is compensated by manual filament feeding
         plan_set_e_position(current_position[E_AXIS]);
-        plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], feedrate/60, active_extruder); //should do nothing
-        plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], target[Z_AXIS], target[E_AXIS], feedrate/60, active_extruder); //move xy back
-        plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], lastpos[Z_AXIS], target[E_AXIS], feedrate/60, active_extruder); //move z back
-        plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], lastpos[Z_AXIS], lastpos[E_AXIS], feedrate/60, active_extruder); //final untretract
+
+        RUNPLAN; //should do nothing
+
+        #ifdef DELTA
+          calculate_delta(lastpos);
+          plan_buffer_line(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], target[E_AXIS], fr60, active_extruder); //move xyz back
+          plan_buffer_line(delta[X_AXIS], delta[Y_AXIS], delta[Z_AXIS], lastpos[E_AXIS], fr60, active_extruder); //final untretract
+        #else
+          plan_buffer_line(target[X_AXIS], target[Y_AXIS], target[Z_AXIS], target[E_AXIS], fr60, active_extruder); //should do nothing
+          plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], target[Z_AXIS], target[E_AXIS], fr60, active_extruder); //move xy back
+          plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], lastpos[Z_AXIS], target[E_AXIS], fr60, active_extruder); //move z back
+          plan_buffer_line(lastpos[X_AXIS], lastpos[Y_AXIS], lastpos[Z_AXIS], lastpos[E_AXIS], fr60, active_extruder); //final untretract
+        #endif
     }
     break;
     #endif //FILAMENTCHANGEENABLE