```
sysutils/node_exporter: Add tests, docs and examples
- Define LICENSE_FILE.
- Sort variables.
- Add a do-test target and prepare a testing environment. One test is skipped
at the moment due to a problem with detecting procfs(5) on FreeBSD.
- Install documentation and examples.
- Change pkg-descr to better match upstream's README.
```
I am not sure about a couple of things, however:
- Is it fine to use `USES=gmake` instead of `TEST_DEPENDS=gmake:devel/gmake`? `USES=gmake` adds a dependency to the build process, which is not ideal.
- The whole `pre-test` target is rather hacky. I was unable to come up with a prettier solution though. Go is a little bit hard to tame.