Allow LIB_DEPENDS to directly depend on .pc files and use pkgconf do find them

[bapt]

Add the pc files straight to depfiles

[antoine]

Ports using this new syntax will have to make sure they use USES=pkgconf right?

[bapt]

there was a question about wether we should make automatically add USES+=pkgconf if that syntax is used, or let the maintainer do it

[antoine]

Maybe a sanity check if the LIB_DEPENDS=pc syntax is used?

[bapt]

Fix small typo

[bapt]

Fix the sanity check

[bapt]

Now that pkgconf supports --path we can simplify a bit finding actual dependencies

[bapt]

typo

[bapt]

search for *.pc before *

[bapt]

ping

[mat]

I think it is missing checks to make sure pkgconf exists.

[bapt]

In the end I'm not sure this is worth it

[bdrewery]

Poudriere would need to learn about this too. https://github.com/freebsd/poudriere/blob/master/src/share/poudriere/common.sh#L4191-L4198

But yeah I'm not sure it is worth it. I'd like to see an argument for why if this is reopened.

[bapt]

This is not reopened, this is abandonned :)