1. Remove `rec` keyword in favor of passing a function to
`stdenv.mkDerivation`;
2. Reorder attributes;
3. Put build only dependencies --- Hare's third party libraries --- into
`nativeBuildInputs`;
4. Remove `preConfigure` hook in favor of setting the `HARECACHE` make
variable;
5. Use `stdenv.hostPlatform.uname.processor` for setting the
architecture needed for cross-compilation;
6. Substitute in place the `HAREFLAGS` make variable instead of the `-a`
flag directly, which is now set on the make variable (this should be
submitted upstream, since the make variable, as of now, does
absolutely nothing);
8. Pass the `-q` flag to `HAREFLAGS` to avoid polluting the logs when
hare is either being called with `test` or `build`;
9. Remove deprecated `agpl3` license in favor of `agpl3Plus`;
10. Add `bonsaictl` as `meta.mainProgram`; and
11. Enable parallel building.
