add kakasi, a Kanji to Hiragana, Katakana or Romaji converter

pkgs/tools/text/kakasi/default.nix

···
+{ stdenv, fetchurl }:
+
+stdenv.mkDerivation rec {
+  name = "kakasi-2.3.6";
+
+  meta = with stdenv.lib; {
+    description = "Kanji Kana Simple Inverter";
+    longDescription = ''
+      KAKASI is the language processing filter to convert Kanji
+      characters to Hiragana, Katakana or Romaji and may be
+      helpful to read Japanese documents.
+    '';
+    homepage    = "http://kakasi.namazu.org/";
+    license     = licenses.gpl2Plus;
+    platforms   = platforms.linux;
+    maintainers = with maintainers; [ iyzsong ];
+  };
+
+  src = fetchurl {
+    url = "http://kakasi.namazu.org/stable/${name}.tar.xz";
+    sha256 = "1qry3xqb83pjgxp3my8b1sy77z4f0893h73ldrvdaky70cdppr9f";
+  };
+}

pkgs/top-level/all-packages.nix

···
 
   hsetroot = callPackage ../tools/X11/hsetroot { };
 
+  kakasi = callPackage ../tools/text/kakasi { };
+
   kde4 = recurseIntoAttrs pkgs.kde411;
 
   kde4_next = recurseIntoAttrs( lib.lowPrioSet pkgs.kde412 );