The Ninja it converts to appears to be here:
https://martine.github.io/ninja/
How does it compare to mk[0]?
mk was make done better for Plan 9.
[0] http://plan9.bell-labs.com/sys/doc/mk.html
Why two versions of the code in Go and C++?
Why? A wheel with less corners...
The Ninja it converts to appears to be here:
https://martine.github.io/ninja/