This reverts commit ccfd26ef14.
These toolchain changes are too problematic, so reverting for now; see
https://github.com/NixOS/nixpkgs/pull/107086#issuecomment-749196366
This reverts commit ccfd26ef14.
These toolchain changes are too problematic, so reverting for now; see
https://github.com/NixOS/nixpkgs/pull/107086#issuecomment-749196366