wine: restore the eval on linux

Without the change the instantiation in `linux` fails as:

    $ nix-instantiate -A wine
    error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:34:12:
           33|
           34|   strict = derivationStrict drvAttrs;
             |            ^
           35|

       … while evaluating derivation 'wine-9.0'
         whose name attribute is located at /tmp/z/nixpkgs/pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'NIX_LDFLAGS' of derivation 'wine-9.0'
         at /tmp/z/nixpkgs/pkgs/applications/emulators/wine/base.nix:121:3:
          120|   # LD_LIBRARY_PATH.
          121|   NIX_LDFLAGS = toString (map (path: "-rpath " + path) (
             |   ^
          122|       map (x: "${lib.getLib x}/lib") ([ stdenv.cc.cc ]

       (stack trace truncated; use '--show-trace' to show the full, detailed trace)

       error: Package ‘apple-sdk-14.4’ in /tmp/z/nixpkgs/pkgs/by-name/ap/apple-sdk/package.nix:111 is not available on the requested hostPlatform:
         hostPlatform.config = "i686-unknown-linux-gnu"
         package.meta.platforms = [
           "x86_64-darwin"
           "i686-darwin"
           "aarch64-darwin"
           "armv7a-darwin"
         ]
         package.meta.badPlatforms = [
           {
             cpu = {
               bits = 32;
             };
           }
         ]
       , refusing to evaluate.

       a) To temporarily allow packages that are unsupported for this system, you can use an environment variable
          for a single invocation of the nix tools.

            $ export NIXPKGS_ALLOW_UNSUPPORTED_SYSTEM=1

          Note: When using `nix shell`, `nix build`, `nix develop`, etc with a flake,
                then pass `--impure` in order to allow use of environment variables.

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

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

pkgs/applications/emulators/wine/base.nix

@@ -25,7 +25,7 @@ let
 
   # Using the 14.4 SDK allows Wine to use `os_sync_wait_on_address` for its futex implementation on Darwin.
   # It does an availability check, so older systems will still work.
-  darwinFrameworks = toBuildInputs pkgArches (pkgs: [ pkgs.apple-sdk_14 ]);
+  darwinFrameworks = lib.optionals stdenv.hostPlatform.isDarwin (toBuildInputs pkgArches (pkgs: [ pkgs.apple-sdk_14 ]));
 
   # Building Wine with these flags isn’t supported on Darwin. Using any of them will result in an evaluation failures
   # because they will put Darwin in `meta.badPlatforms`.