Added fix for SF Arc Point fillet procedure

Marlin/Configuration.h

 // Data from: http://www.doc-diy.net/photo/rc-1_hacked/
 // #define PHOTOGRAPH_PIN     23
 
+// SF send wrong arc g-codes when using Arc Point as fillet procedure
+//#define SF_ARC_FIX
+
 #include "Configuration_adv.h"
 #include "thermistortables.h"
 

Marlin/Marlin.pde

 
 void get_arc_coordinates()
 {
+#ifdef SF_ARC_FIX
+   bool relative_mode_backup = relative_mode;
+   bool relative_mode = true;
+#endif
    get_coordinates();
+#ifdef SF_ARC_FIX
+   relative_mode=relative_mode_backup;
+#endif
+
    if(code_seen('I')) {
      offset[0] = code_value();
    }