This platform has a growing desktop and embedded user base, and is fully
supported by Go. The only necessary change is the mapping between
`uname -m` output and GOARCH.
Due to non-technical reasons [1], there is currently no Docker official
image that provides linux/loong64 support, so Docker-based builds are
not included in this commit for now.
[1]: https://github.com/docker-library/official-images/issues/16404
