Add ability to override the download URL manually

[Ahajha]

No description provided.

[keith]

how does this work for multiple platforms? since a toolchain can target N platforms but this is only 1 url?

[Ahajha]

that would need a little more work than I have here. worst case you can do a select? the target use case was just a local file override, where only the current platform matters.

[keith]

you can't select in the module.bazel, maybe what this use case wants instead is a --override_repository? i guess the problem with that is you'd have to handle the BUILD file manually

[Ahajha]

ah right. yea i guess this just can't do multiplatform stuff then in its current state.

[Ahajha]

it gets a little weird because you'd need to plumb through a way to put the platform name in the url, and i don't know if there's a clear cut way to do that.

[keith]

modeling after toolchains_llvm the solution would be to make urls or something as a dictionary of platform to url. i started on that somewhere but bailed since we didn't have a use case

[Ahajha]

yea open to suggestions here. the only use case we really have is testing with a local package for our nightly qualifications, so any other way we can do that is fine with me.

[keith]

#8

[keith]

i did have this one open

[Ahajha]

i wouldn't object to replacing this with that. i saw it at the time but not until i had already merged this one lol.