Issue #2483. Simplistic fix to suit 90%+ of use cases.

speed_override is an array, one flag per spindle. However the "active M-codes"
array and the state-tags have no way to represent this.
For the moment this only considers spindle 0.
A proper fix would require an entry in the settings struct to exho the count
of spindles.
Also, the state tag is limited to 64 bits, spending 24 of those on spindles
that probably don't exist seems wrong.

Author: andypugh

src/emc/rs274ngc/interp_write.cc

@@ -161,10 +161,12 @@ int Interp::write_m_codes(block_pointer block,   //!< pointer to a block of RS27
     (settings->mist) ? 7 : (settings->flood) ? -1 : 9;
   emz[5] =                      /* 5 flood       */
     (settings->flood) ? 8 : -1;
+  // This only considers spindle 0. This function //
+  //doesn't even know how many spindles there are //
   if (settings->feed_override) {
-    if (settings->speed_override) emz[6] =  48;
+    if (settings->speed_override[0]) emz[6] =  48;
     else emz[6] = 50;
-  } else if (settings->speed_override) {
+  } else if (settings->speed_override[0]) {
     emz[6] = 51;
   } else emz[6] = 49;
 
@@ -315,7 +317,7 @@ int Interp::write_state_tag(block_pointer block,
     state.flags[GM_FLAG_FLOOD] = (settings->flood);
 
     state.flags[GM_FLAG_FEED_OVERRIDE] = settings->feed_override;
-    state.flags[GM_FLAG_SPEED_OVERRIDE] = settings->speed_override;
+    state.flags[GM_FLAG_SPEED_OVERRIDE] = settings->speed_override[0];
 
     state.flags[GM_FLAG_ADAPTIVE_FEED] = (settings->adaptive_feed);