a) For `nixos-rebuild` you can set
  { nixpkgs.config.allowUnsupportedSystem = true; }
in configuration.nix to override this.

b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
  { allowUnsupportedSystem = true; }
to ~/.config/nixpkgs/config.nix.

    |             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ expected u8, found i8
    |
    = note: expected type `*const u8`
               found type `*const i8`

error: aborting due to previous error

builder for '/nix/store/06j5q5rshfwskif8vvy027ihhdyvbz5x-rust_way-cooler-0.8.0.drv' failed with exit code 101
cannot build derivation '/nix/store/6jv88rg4j1y1if3cy3rppb3yx5p6445y-way-cooler-with-extensions-0.8.0.drv': 1 dependencies couldn't be built
�[31;1merror:�[0m build of '/nix/store/6jv88rg4j1y1if3cy3rppb3yx5p6445y-way-cooler-with-extensions-0.8.0.drv' failed

patching script interpreter paths in /nix/store/ws490xxqd2hgh14hn6gs23rhja31q86f-rust_way-cooler-0.8.0
checking for references to /build in /nix/store/ws490xxqd2hgh14hn6gs23rhja31q86f-rust_way-cooler-0.8.0...
building '/nix/store/p4n35rwqpd9v184q7jydgs1imhvra5jx-way-cooler-with-extensions-0.8.0.drv'...
/nix/store/sl97zxa6ha37a8rprqjc7ypk3p1aw0g7-rust_wc-bg-0.3.0/lib:
link: /nix/store/ws490xxqd2hgh14hn6gs23rhja31q86f-rust_way-cooler-0.8.0/lib/link
/nix/store/6b8fq1dbrlynhglrq0c7fpk8dh6qa9yl-rust_wc-grab-0.3.0/lib:
link: /nix/store/ws490xxqd2hgh14hn6gs23rhja31q86f-rust_way-cooler-0.8.0/lib/link
/nix/store/wxi4zqpfnjw0475317af4f8x413jfjsi-rust_wc-lock-0.2.1/lib:
link: /nix/store/ws490xxqd2hgh14hn6gs23rhja31q86f-rust_way-cooler-0.8.0/lib/link
/nix/store/91fk69pan5kvhsqdgrb9ik47fkqfhdx0-way-cooler-with-extensions-0.8.0