some fixes

LibSidServo/main.h

@@ -28,6 +28,7 @@
 #include "sidservo.h"
 
 extern conf_t Conf;
+extern limits_t Xlimits, Ylimits;
 double nanotime();
 void getModData(coordval_pair_t *c, movestate_t *xst, movestate_t *yst);
 typedef struct{
@@ -43,10 +44,6 @@ double LS_calc_slope(less_square_t *l, double x, double t);
 
 // unused arguments of functions
 #define _U_         __attribute__((__unused__))
-// break absent in `case`
-#define FALLTHRU    __attribute__ ((fallthrough))
-// and synonym for FALLTHRU
-#define NOBREAKHERE __attribute__ ((fallthrough))
 // weak functions
 #define WEAK        __attribute__ ((weak))