feat(nix/buildLisp): pass implementation description instead of name r/2773

Instead of using a string to refer to an internal set defined in
buildLisp, we just expose the relevant sets (as nix.buildLisp.sbcl,
nix.buildLisp.ecl, …) and receive them as the `implementation`
argument directly. This has several advantages:

* It becomes easier to extend buildLisp, even for downstream users:
  Since you can just pass your own set, there's nothing stopping you
  from adding support for another implementation in a downstream
  derivation without having to edit the buildLisp file in any way which
  is great if you're using e. g. builtins.fetchGit to import it.

* Users can mess with the implementation set by changing out some parts
  of it for customization purposes. Note that currently the sets use a
  lot of self-references which aren't even bound by a fix-point, so to
  make this work smoothly, we'd need to add some overriding mechanism.

* The buildLisp code becomes quite a bit clearer. Since we're now always
  dealing with the implementation set, the confusing distinction between
  `impl`, `impl.name` and `implementation` no longer exists. `impl` is
  now exclusively an abbreviation of `implementation` (we could make
  this more consistent in the future even).

Change-Id: I36d68069dd1315610b2f7159941507b465469b7c
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3368
Reviewed-by: tazjin <mail@tazj.in>
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI

0 files changed, 0 insertions, 0 deletions