gauche: mark not broken on darwin

Update to use the new sdk.

pkgs/development/interpreters/gauche/default.nix

···
     maintainers = with maintainers; [ mnacamura ];
     license = licenses.bsd3;
     platforms = platforms.unix;
-    broken = stdenv.isDarwin;
   };
 }

pkgs/top-level/all-packages.nix

···
 
   ganttproject-bin = callPackage ../applications/misc/ganttproject-bin { };
 
-  gaucheBootstrap = callPackage ../development/interpreters/gauche/boot.nix { };
+  gaucheBootstrap = darwin.apple_sdk_11_0.callPackage ../development/interpreters/gauche/boot.nix { };
 
-  gauche = callPackage ../development/interpreters/gauche { };
+  gauche = darwin.apple_sdk_11_0.callPackage ../development/interpreters/gauche { };
 
   gazelle-origin = python3Packages.callPackage ../tools/misc/gazelle-origin { };