Clearly specify X/Y to G2.

[cho45]

Grbl does not move without X/Y in G2. (ref https://github.com/grbl/grbl/blob/0427fd5/grbl/gcode.c#L684 Block without X/YZ/ is ignored...)

This patch just adds current X/Y to G2.

This may be fixed in grbl side. But this generates more versatile gcode with no side effects.

[corna]

I tested it with LinuxCNC and it works correctly.
With Mach3 an axis word is probably mandatory (see here, "When the XY-plane is selected [...]. The axis words are all optional except that at least one of X and Y must be used."), therefore you should change the commit message to something more generic (like "add explicit X/Y coordinates during G2 movements")

[corna]

Merged, thanks

[cho45]

Thank you for fast response!