Updated motion in units per revolution mode (G95) to handle spindle RPM changes.

Changed initial wait for two index pulses to check RPM > 0 before starting such motion.

planner.h

@@ -147,6 +147,7 @@ typedef struct {
                                     // i.e. arcs, canned cycles, and backlash compensation.
   float previous_unit_vec[N_AXIS];  // Unit vector of previous path line segment
   float previous_nominal_speed;     // Nominal speed of previous path line segment
+  float actual_rpm;                 // Updated when in units per revolution blocks (G95) mode.
 } planner_t;
 
 // Initialize and reset the motion plan subsystem
@@ -194,4 +195,6 @@ void plan_feed_override (override_t feed_override, override_t rapid_override);
 
 void plan_data_init (plan_line_data_t *plan_data);
 
+void plan_sync_velocity (void *block);
+
 #endif