Circle-CI doesn't like build because of gocv

[Saxon Milton]

Circle-CI doesn’t like building because of our new friend gocv. Do we need to modify the CI config, or maybe do some sort of conditional compilation ?

[Alan Noble]

I think we need both. If we only cared about running gocv on Linux/Raspbian, then we could use conditional compilation via _linux files (as we did for audio), but CircleCI (which is Linux based) will still need to skip it.

Keep in mind that we should maintain portability across all platforms, in particular Windows.

[Saxon Milton]

I think that we should use build tags. One for windows (gocv doesn’t support windows unfortunately) one for linux (not CI) and one for CI. Build tags allows you to come up with arbitrary tag names, whereas conditional compilation using file names must have particular literals. Our CI config build command would then use the -tags flag and select the appropriate one.