Fix up the code to eliminate warnings

Marlin/Marlin_main.cpp

 static float destination[NUM_AXIS] = { 0, 0, 0, 0 };
 
 static float offset[3] = { 0, 0, 0 };
-static bool home_all_axis = true;
+
+#ifndef DELTA
+  static bool home_all_axis = true;
+#endif
+
 static float feedrate = 1500.0, next_feedrate, saved_feedrate;
 static long gcode_N, gcode_LastN, Stopped_gcode_LastN = 0;
 
 
 static char cmdbuffer[BUFSIZE][MAX_CMD_SIZE];
 #ifdef SDSUPPORT
-static bool fromsd[BUFSIZE];
-#endif //!SDSUPPORT
+  static bool fromsd[BUFSIZE];
+#endif
 static int bufindr = 0;
 static int bufindw = 0;
 static int buflen = 0;
     feedrate = oldFeedRate;
 }
 
-static void do_blocking_move_relative(float offset_x, float offset_y, float offset_z) {
-    do_blocking_move_to(current_position[X_AXIS] + offset_x, current_position[Y_AXIS] + offset_y, current_position[Z_AXIS] + offset_z);
-}
-
 static void setup_for_endstop_move() {
     saved_feedrate = feedrate;
     saved_feedmultiply = feedmultiply;
     }
 
     int verbose_level = 1;
-    float x_tmp, y_tmp, z_tmp, real_z;
 
     if (code_seen('V') || code_seen('v')) {
       verbose_level = code_value_long();
     // When the bed is uneven, this height must be corrected.
     if (!dryrun)
     {
+      float x_tmp, y_tmp, z_tmp, real_z;
       real_z = float(st_get_position(Z_AXIS)) / axis_steps_per_unit[Z_AXIS];  //get the real Z (since the auto bed leveling is already correcting the plane)
       x_tmp = current_position[X_AXIS] + X_PROBE_OFFSET_FROM_EXTRUDER;
       y_tmp = current_position[Y_AXIS] + Y_PROBE_OFFSET_FROM_EXTRUDER;
     }
   }
 
-  float area = .0;
   if (code_seen('D')) {
     float diameter = code_value();
     // setting any extruder filament size disables volumetric on the assumption that
  * M503: print settings currently in memory
  */
 inline void gcode_M503() {
-  Config_PrintSettings(code_seen('S') && code_value == 0);
+  Config_PrintSettings(code_seen('S') && code_value() == 0);
 }
 
 #ifdef ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED
     SERIAL_ECHOLN(MSG_INVALID_EXTRUDER);
   }
   else {
-    boolean make_move = false;
+    #if EXTRUDERS > 1
+      bool make_move = false;
+    #endif
     if (code_seen('F')) {
-      make_move = true;
+      #if EXTRUDERS > 1
+        make_move = true;
+      #endif
       next_feedrate = code_value();
       if (next_feedrate > 0.0) feedrate = next_feedrate;
     }
 
 void get_coordinates()
 {
-  bool seen[4]={false,false,false,false};
   for(int8_t i=0; i < NUM_AXIS; i++) {
     if(code_seen(axis_codes[i]))
     {
       destination[i] = (float)code_value() + (axis_relative_modes[i] || relative_mode)*current_position[i];
-      seen[i]=true;
     }
     else destination[i] = current_position[i]; //Are these else lines really needed?
   }

Marlin/cardreader.cpp

   if (workDirDepth > 0) {
     --workDirDepth;
     workDir = workDirParents[0];
-    for (int d = 0; d < workDirDepth; d++)
+    for (uint16_t d = 0; d < workDirDepth; d++)
       workDirParents[d] = workDirParents[d+1];
   }
 }

Marlin/configurator/config/language.h

 #endif
 
 #ifdef CUSTOM_MENDEL_NAME
+  #undef MACHINE_NAME
   #define MACHINE_NAME CUSTOM_MENDEL_NAME
 #endif
 
 #ifndef MACHINE_UUID
-   #define MACHINE_UUID "00000000-0000-0000-0000-000000000000"
+  #define MACHINE_UUID "00000000-0000-0000-0000-000000000000"
 #endif
 
 

Marlin/language.h

 #endif
 
 #ifdef CUSTOM_MENDEL_NAME
+  #undef MACHINE_NAME
   #define MACHINE_NAME CUSTOM_MENDEL_NAME
 #endif
 

Marlin/pins.h

 #endif
 
 #ifdef DISABLE_MAX_ENDSTOPS
+  #undef X_MAX_PIN
+  #undef Y_MAX_PIN
+  #undef Z_MAX_PIN
   #define X_MAX_PIN          -1
   #define Y_MAX_PIN          -1
   #define Z_MAX_PIN          -1
 #endif
 
 #ifdef DISABLE_MIN_ENDSTOPS
+  #undef X_MIN_PIN
+  #undef Y_MIN_PIN
+  #undef Z_MIN_PIN
   #define X_MIN_PIN          -1
   #define Y_MIN_PIN          -1
   #define Z_MIN_PIN          -1

Marlin/planner.cpp

 
   int moves_queued = movesplanned();
 
-  // slow down when de buffer starts to empty, rather than wait at the corner for a buffer refill
-  bool mq = moves_queued > 1 && moves_queued < BLOCK_BUFFER_SIZE / 2;
-  #ifdef OLD_SLOWDOWN
-    if (mq) feed_rate *= 2.0 * moves_queued / BLOCK_BUFFER_SIZE;
-  #endif
-
-  #ifdef SLOWDOWN
-    //  segment time im micro seconds
-    unsigned long segment_time = lround(1000000.0/inverse_second);
-    if (mq) {
-      if (segment_time < minsegmenttime) {
-        // buffer is draining, add extra time.  The amount of time added increases if the buffer is still emptied more.
-        inverse_second = 1000000.0 / (segment_time + lround(2 * (minsegmenttime - segment_time) / moves_queued));
-        #ifdef XY_FREQUENCY_LIMIT
-          segment_time = lround(1000000.0 / inverse_second);
-        #endif
+  // Slow down when the buffer starts to empty, rather than wait at the corner for a buffer refill
+  #if defined(OLD_SLOWDOWN) || defined(SLOWDOWN)
+    bool mq = moves_queued > 1 && moves_queued < BLOCK_BUFFER_SIZE / 2;
+    #ifdef OLD_SLOWDOWN
+      if (mq) feed_rate *= 2.0 * moves_queued / BLOCK_BUFFER_SIZE;
+    #endif
+    #ifdef SLOWDOWN
+      //  segment time im micro seconds
+      unsigned long segment_time = lround(1000000.0/inverse_second);
+      if (mq) {
+        if (segment_time < minsegmenttime) {
+          // buffer is draining, add extra time.  The amount of time added increases if the buffer is still emptied more.
+          inverse_second = 1000000.0 / (segment_time + lround(2 * (minsegmenttime - segment_time) / moves_queued));
+          #ifdef XY_FREQUENCY_LIMIT
+            segment_time = lround(1000000.0 / inverse_second);
+          #endif
+        }
       }
-    }
+    #endif
   #endif
-  //  END OF SLOW DOWN SECTION    
 
   block->nominal_speed = block->millimeters * inverse_second; // (mm/sec) Always > 0
   block->nominal_rate = ceil(block->step_event_count * inverse_second); // (step/sec) Always > 0

Marlin/qr_solve.cpp

   double norm;
   double scale;
   double ssq;
-  double value;
 
   if ( n < 1 || incx < 1 )
   {

Marlin/stepper.cpp

   int motor_current_setting[3] = DEFAULT_PWM_MOTOR_CURRENT;
 #endif
 
-static bool old_x_min_endstop = false,
-            old_x_max_endstop = false,
-            old_y_min_endstop = false,
-            old_y_max_endstop = false,
-            old_z_min_endstop = false,
-            #ifndef Z_DUAL_ENDSTOPS
-            old_z_max_endstop = false;
-            #else
-              old_z_max_endstop = false,
-              old_z2_min_endstop = false,
-              old_z2_max_endstop = false;
-            #endif
+#if defined(X_MIN_PIN) && X_MIN_PIN >= 0
+  static bool old_x_min_endstop = false;
+#endif
+#if defined(X_MAX_PIN) && X_MAX_PIN >= 0
+  static bool old_x_max_endstop = false;
+#endif
+#if defined(Y_MIN_PIN) && Y_MIN_PIN >= 0
+  static bool old_y_min_endstop = false;
+#endif
+#if defined(Y_MAX_PIN) && Y_MAX_PIN >= 0
+  static bool old_y_max_endstop = false;
+#endif
+
+static bool old_z_min_endstop = false, old_z_max_endstop = false;
+
+#ifdef Z_DUAL_ENDSTOPS
+  static bool old_z2_min_endstop = false, old_z2_max_endstop = false;
+#endif
 
 static bool check_endstops = true;
 
 }
 
 void microstep_init() {
-  const uint8_t microstep_modes[] = MICROSTEP_MODES;
-
   #if defined(E1_MS1_PIN) && E1_MS1_PIN >= 0
     pinMode(E1_MS1_PIN,OUTPUT);
     pinMode(E1_MS2_PIN,OUTPUT); 
     pinMode(Z_MS2_PIN,OUTPUT);
     pinMode(E0_MS1_PIN,OUTPUT);
     pinMode(E0_MS2_PIN,OUTPUT);
-    for (int i = 0; i <= 4; i++) microstep_mode(i, microstep_modes[i]);
+    const uint8_t microstep_modes[] = MICROSTEP_MODES;
+    for (int i = 0; i < sizeof(microstep_modes) / sizeof(microstep_modes[0]); i++)
+      microstep_mode(i, microstep_modes[i]);
   #endif
 }
 

Marlin/ultralcd.h

   #ifdef DOGLCD
     extern int lcd_contrast;
     void lcd_setcontrast(uint8_t value);
+    static unsigned char blink = 0; // Variable for visualization of fan rotation in GLCD
   #endif
 
-  static unsigned char blink = 0;	// Variable for visualization of fan rotation in GLCD
-
   #define LCD_MESSAGEPGM(x) lcd_setstatuspgm(PSTR(x))
   #define LCD_ALERTMESSAGEPGM(x) lcd_setalertstatuspgm(PSTR(x))