pkgsi686Linux: only throw with aliases enabled (#427243)

    # All packages built for i686 Linux.

    # Used by wine, firefox with debugging version of Flash, ...

    pkgsi686Linux =

      if stdenv.hostPlatform.isLinux && stdenv.hostPlatform.isx86 then

      let

        isSupported = stdenv.hostPlatform.isLinux && stdenv.hostPlatform.isx86;

      in

      if !config.allowAliases || isSupported then

        nixpkgsFun {

          overlays = [

            (self': super': {

            (

              self': super':

              {

                pkgsi686Linux = super';

            })

              }

              // lib.optionalAttrs (!isSupported) {

                # Overrides pkgsi686Linux.stdenv.mkDerivation to produce only broken derivations,

                # when used on a non x86_64-linux platform in CI.

                # TODO: Remove this, once pkgsi686Linux can become a variant.

                stdenv = super'.stdenv // {

                  mkDerivation =

                    args:

                    (super'.stdenv.mkDerivation args).overrideAttrs (prevAttrs: {

                      meta = prevAttrs.meta or { } // {

                        broken = true;

                      };

                    });

                };

              }

            )

          ] ++ overlays;

          ${if stdenv.hostPlatform == stdenv.buildPlatform then "localSystem" else "crossSystem"} = {

            config = lib.systems.parse.tripleFromSystem (