Doom hooks into flycheck's emacs-lisp checker to load itself. This does
not involve its profile loader, so this bypasses our profile dir
customization.
Hook into this hook to add that customization back.
`doom-start` locates the profile init file relative to
`doom-profile-dir` when running interactively, which we customize (either
directly or by setting `doom-profile-data-dir`). But when running
noninteractively, it uses `doom-profile-init-file`, which always loads
relative to `doom-data-dir`.
We cannot point `doom-data-dir` into the store, so this breaks us.
Work around it by advicing `doom-profile-data-dir` to locate the init
file relative to `doom-profile-dir` too. Try to make this more safe by
erroring out if called on a non-default profile.
All of this feels questionable, but I really want `doom doctor` to
work...
`straight--load-build-cache` is not autoloaded, so we fail if it has not
been loaded yet. Apparently it usually is when we hit this override
interactively, but Doom CLI can call our override early enough we need
this.
Instead of passing the path down from the profile loader to init.el,
just substitute the path into init.el.
This requires moving DOOMDIR generation into the same derivation as
profile build to avoid a circular dependency.
