opencc: fix cross compilation

pkgs/tools/text/opencc/default.nix

@@ -4,6 +4,7 @@
   fetchFromGitHub,
   cmake,
   python3,
+  opencc,
 }:
 
 stdenv.mkDerivation rec {
@@ -17,10 +18,14 @@ stdenv.mkDerivation rec {
     sha256 = "sha256-N7nazA0xoQ2ewOGDiJg1vBBYMdF1/qiCfNjG5CFFbuk=";
   };
 
-  nativeBuildInputs = [
-    cmake
-    python3
-  ];
+  nativeBuildInputs =
+    [
+      cmake
+      python3
+    ]
+    ++ lib.optionals (!stdenv.buildPlatform.canExecute stdenv.hostPlatform) [
+      opencc # opencc_dict
+    ];
 
   meta = with lib; {
     homepage = "https://github.com/BYVoid/OpenCC";