This was meant to happen but did not previously happen. It is not
ideal to do it now but better do it while we still can.
In short, this removes one half of the variables API (keeps
constants as they are) and repurposes the API to be only for
constants. This is also better for consistency to match errors.
This finally enables looking up things from the current unit
rather than from a backing storage in the Eolian state. This
also means that the benefits of having a unit system will
finally be visible.
This adds new APIs that deal with the new documentation syntax
provided by Eolian. The old doc comment APIs are considered
deprecated from now on and will be removed.
@feature
Also added API to retrieve value of a variable (forgot about that one)
and made it impossible to create extern constants (doesn't make sense)
as well as made it impossible to give extern globals values.
Nothing parses yet, and no API is exposed. Also, move the remaining instances of file
inside of existing structures to Eolian_Object and parse basename only once.