kakasi: make tests run, but disable

pkgs/tools/text/kakasi/default.nix

@@ -21,4 +21,14 @@ stdenv.mkDerivation rec {
     url = "http://kakasi.namazu.org/stable/${name}.tar.xz";
     sha256 = "1qry3xqb83pjgxp3my8b1sy77z4f0893h73ldrvdaky70cdppr9f";
   };
+
+  postPatch = ''
+    for a in tests/kakasi-* ; do
+      substituteInPlace $a \
+        --replace "/bin/echo" echo
+    done
+  '';
+
+  doCheck = false; # fails 1 of 6 tests
+
 }