Unblock native XYZAC TP oracle

patches/linuxcnc/0001-export-native-task-heartbeat.patch

@@ -0,0 +1,26 @@
+diff --git a/src/emc/task/emctaskmain.cc b/src/emc/task/emctaskmain.cc
+--- a/src/emc/task/emctaskmain.cc
++++ b/src/emc/task/emctaskmain.cc
+@@ -3490,4 +3490,9 @@ int main(int argc, char *argv[])
+ 	// since emcStatus was passed to the WM init functions, it
+ 	// will be updated in the _update() functions above. There's
+ 	// no need to call the individual functions on all WM items.
++	// EMC_TASK_STAT_MSG::heartbeat is the native task-cycle oracle used by
++	// external clients.  Keep it monotonic and publish it with this cycle's
++	// status image so a reader can identify every task tick without relying on
++	// wall-clock sampling.
++	emcStatus->task.heartbeat++;
+ 	emcStatusBuffer->write(emcStatus);
+
+diff --git a/src/emc/usr_intf/axis/extensions/emcmodule.cc b/src/emc/usr_intf/axis/extensions/emcmodule.cc
+--- a/src/emc/usr_intf/axis/extensions/emcmodule.cc
++++ b/src/emc/usr_intf/axis/extensions/emcmodule.cc
+@@ -409,4 +409,7 @@ static PyMemberDef Stat_members[] = {
+     {(char*)"echo_serial_number", T_INT, O(echo_serial_number), READONLY},
+     {(char*)"echo_serial_number", T_INT, O(echo_serial_number), READONLY},
+     {(char*)"state", T_INT, O(status), READONLY},
++    {(char*)"task_heartbeat", T_UINT, O(task.heartbeat), READONLY,
++        "Native EMC task-loop heartbeat.  This counter is incremented by the "
++        "LinuxCNC task thread and is suitable for identifying native status ticks."},
+
+ // task