FeatureNew: Make all checks subproject-specific

We now pass the current subproject to every FeatureNew and
FeatureDeprecated call. This requires a bunch of rework to:

1. Ensure that we have access to the subproject in the list of
   arguments when used as a decorator (see _get_callee_args).
2. Pass the subproject to .use() when it's called manually.
3. We also can't do feature checks for new features in
   meson_options.txt because that's parsed before we know the
   meson_version from project()

0 files changed, 0 insertions, 0 deletions