stdenv: Fix overriding + `overrideAttrs`

The old stdenv adapters were subtly wrong in two ways:

 - `overrideAttrs` leaked the original, unoverridden `mkDerivation`.

 - `stdenv.override` would throw away any manually-set `mkDerivation`
   from a stdenv reverting to the original.

Now, `mkDerivation` is controlled (nearly directly) via an argument, and
always correctly closes over the final ("self") stdenv. This means the
adapters can work entirely via `.override` without any manual `stdenv //
...`, and both those issues are fixed.

Note hashes are changed, because stdenvs no previously overridden like
`stdenvNoCC` and `crossLibcStdenv` now are. I had to add some
`dontDisableStatic = true` accordingly. The flip side however is that
since the overrides compose, we no longer need to override anything but
the default `stdenv` from which all the others are created.

0 files changed, 0 insertions, 0 deletions