While the word 'simply' is usually added to encourage readers, it often has the
opposite effect and may even appear condescending, especially when the reader
runs into trouble trying to apply the suggestions from the documentation. It is
almost always an improvement to simply drop the word from the sentence.
(there are more possible improvements like this, we can apply those in separate
PRs)
1. Clarify what is the reason for importing and to where it saves
2. Clarify that packages.sqlite is a temporary file
3. Link to section about native dependencies from first mention of ql.nix
The previous approach of trying to make both the `override` mechanism from
`mkDerivation` and the `overrideScope'` mechanism from `newScope` work together
resulted in hard to understand code, and there was a bug where once overridden
packages would lose the changes on next override with `packageOverrides`.
It's not ideal still, because Lisps created by `mkDerivation` will lose their
`pkgs` after using `override`.
The previous approach of manually repeating a complex pattern inside Common Lisp
implementation package declarations was fragile and hard to change. After
reading python and lua modules code in Nixpkgs, I was able to come up with
something better.
The function `wrapLisp` doesn't need to be inside package declarations so all
the code for wrapping Lisps can be in `all-packages.nix`.
This works by wrapping the `override` function created from `mkDerivation` to
accept a new argument `packageOverrides`.
One problem with this is that `override.__functionArgs` disappears. But one can
look at the source code of a package to discover what can be overridden.
