At the moment we have a simple subpkgdesc() function that can only
parse "pkgdesc" from subpackages, without support for any variables.
But we have a quite nice variable parser now that can be extended
to work for subpackages.
Simply put this works by:
- Finding the lines that belong to the subpackage function
- Stripping indentation (tab)
- Parsing relevant attributes similar to the apkbuild() function
The "subpackages" in the parsed APKBUILD are replaced by a dict
of subpkgname: {"pkgdesc": "...", "depends": "..."} which are
parsed from the subpackage function (if found).
This makes it possible to get the "depends" of a subpackage.