Implement support for requiring dependency version ranges

[sdroege]

This now supports expressions in the form

• "1.2" or ">= 1.2" for at least version 1.2
• ">= 1.2, < 2.0" for at least version 1.2 and less than version 2.0

Fixes #60

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@gdesmott Does this look reasonable to you? As discussed, semver can't really be used here because pkg-config versions don't follow semver. A version of "1.2" is semver ">= 1.2, < 2.0" and that is more semantics than pkg-config versions have.

[gdesmott]

Does this look reasonable to you?

I think so. Let's go for that then. I didn't look at the implementation yet but the syntax is ok.

Could you please add some tests as well?

[sdroege]

Could you please add some tests as well?

Sure, I was waiting for an OK for the syntax before spending time on writing tests :)

[gdesmott]

This MR does not break API right? Just so I know how to version the release once it's merged.

[sdroege]

It doesn't break API. If a crate starts using more complex version expressions then it needs to be able to actually handle them though: it will get them passed as version to the closure for building the dependency internally. That doesn't seem like API breakage though as it only happens once the crate uses the new feature.

[sdroege]

Added two simple tests for this.

[gdesmott]

Looks like this test is failing on CI: https://github.com/gdesmott/system-deps/actions/runs/6695863075/job/18192357484?pr=82

(Yeah I need the fix the other jobs)

[gdesmott]

(Yeah I need the fix the other jobs)

I just did so you can rebase your branch for easy CI testing.

[sdroege]

Looks like this test is failing on CI

Because pkgconf and pkg-config have completely different error messages. I've added both of them now.

[gdesmott]

Thanks for the patch. I just released 6.2.0 with it.