Cross compiling doesn't always use the correct settings for subrepos.

[cemeceme]

When cross compiling, the wrong settings are getting used for subrepos sometimes.
I haven't been able to create a minimal environment that reproduces this behavior unfortunately.

What I can say so far is:

• The wrong settings seem to be used in some subrepos but not the root project.
  • However it may also be dependent on how the subrepo gets included. I.e. local_repository vs github_repo.
• In build.log, the labels using the wrong settings still correctly contain an @<architecture> tag.
• The settings in question is from a plugin.
• The issue is deterministic: it is always the same subrepo with the same plugin settings that are incorrect.
• Any .plzconfig_arch or .plzconfig files in the subrepo get ignored, using the plugin default instead.
  • Overriding in the root .plzconfig does have an effect, but the root .plzconfig_arch does not.
  • However, a different plugin in the project uses the root configuration or its own config for the target arch with no problems.

Also, I would like to mention that there doesnt seem to be any documentation specifying how settings should be overridden.
Should subrepo settings be ignored entirely, be overrideable or be the definitive settings for that subrepo? Some detail on this would be useful since there are some other inconsistencies regarding this topic too.