fix: adjust liboqs pkgconfig version detection to new scheme

[tranzystorekk]

Noticed this part wasn't touched after the versioning update, this works correctly with it.

[thomwiggers]

Do we need to do a patch release for this or are we good?

Relatedly I'm thinking we should probably split out the vendored stuff in its own crate, because I suppose we might want to separately bump oqs, oqs-sys's minimum requirement and the default-included code...

[tranzystorekk]

The old code tries to match pkgconfig with a nonsense version range, which doesn't break anything AFAIU, but also plain doesn't work as intended, so a patch seems desirable.

As for your second point, I'm not sure I follow, or maybe I don't see the benefit of separating the vendored code.

[thomwiggers]

Imagine liboqs publishes version 0.9.1, then I would like to package oqs-sys version 0.9.x+liboqs-0.9.1. But that would also bump the minimum requirement for pkgconfig even if it should still be compatible with liboqs 0.9.0.

Moving the vendored code into a separate crate would allow Cargo's dependency resolver to resolve such conflicts. I suppose that alternatively we could get rid of the version autodetection but that means we have yet another version code point to keep track of when updating...

[tranzystorekk]

But that would also bump the minimum requirement for pkgconfig even if it should still be compatible with liboqs 0.9.0.

Huh, I haven't thought about that, but my reasoning was if we declare liboqs-0.9.1 we should vendor or accept via pkgconfig only versions that include at least fixes from that baseline version, so patch numbers >=1.

[thomwiggers]

Patch releases could also include improvements, such as new implementations, though. It's a bit tricky.

Anyway I don't care about this too much, we'll see if the OS vendors yell at us down the line.

[tranzystorekk]

Looks like 0.9.1 wasn't released on crates.io, presumably a simple omission?

[thomwiggers]

I was waiting on the merge queue and then entered my weekend. I have just released it.

(I should ideally set up CI to do all of this for me... but that's a bunch of engineering effort.)