Expose pyodide_abi_version, pyodide_root, and python_include_dir in pyodide config cli

[ryanking13]

This PR exposes three new variables in pyodide config CLI. I think they are useful in package builds.

• pyodide_root: We can use it when we need to access some of the files in the xbuildenv.
• pyodide_abi_version: As it is going to be used in PEP 783, I think it is good to expose it in cli.
• python_include_dir: It can be used in some packages that do not follow PEP517 (e.g. RobotRaconteur)

[agriyakhetarpal]

Thanks, @ryanking13! Sorry, I didn't notice that you were working on this, so #187 is also changing the same files. I think we should proceed with this PR first, as I have some more merge conflicts to resolve anyway.

As this PR adds python_include_dir, it reminded me of my older PR #14. Do you think I should revive that PR after this is merged? At that stage, I wasn't acquainted with our codebase and the general Pyodide ecosystem, but I think I am now. :)

[ryanking13]

Thanks, @ryanking13! Sorry, I didn't notice that you were working on this, so #187 is also changing the same files. I think we should proceed with this PR first, as I have some more merge conflicts to resolve anyway.

Yes, sorry to introduce a code conflict. I'll go ahead and merge this PR, so you can rebase yours.

As this PR adds python_include_dir, it reminded me of my older PR #14. Do you think I should revive that PR after this is merged? At that stage, I wasn't acquainted with our codebase and the general Pyodide ecosystem, but I think I am now. :)

Sure, please do. I left some reviews in that PR a while ago.