mecab: add libiconv as buildInputs

#257480 added utf8 support but mecab depends on libiconv to convert between
charsets. Thus, on MacOS it doesn't works

pkgs/tools/text/mecab/base.nix

@@ -1,4 +1,4 @@
-{ fetchurl }:
+{ fetchurl, libiconv }:
 
 finalAttrs: {
   version = "0.996";
@@ -9,6 +9,8 @@ finalAttrs: {
     hash = "sha256-4HMyV4MTW3LmZhRceBu0j62lg9UiT7JJD7bBQDumnFk=";
   };
 
+  buildInputs = [ libiconv ];
+
   configureFlags = [
     "--with-charset=utf8"
   ];

pkgs/tools/text/mecab/default.nix

@@ -1,7 +1,7 @@
-{ lib, stdenv, fetchurl, mecab-ipadic }:
+{ lib, stdenv, fetchurl, mecab-ipadic, libiconv }:
 
 let
-  mecab-base = import ./base.nix { inherit fetchurl; };
+  mecab-base = import ./base.nix { inherit fetchurl libiconv; };
 in
 stdenv.mkDerivation (finalAttrs: ((mecab-base finalAttrs) // {
   pname = "mecab";

pkgs/tools/text/mecab/nodic.nix

@@ -1,7 +1,7 @@
-{ stdenv, fetchurl }:
+{ stdenv, fetchurl, libiconv }:
 
 let
-  mecab-base = import ./base.nix { inherit fetchurl; };
+  mecab-base = import ./base.nix { inherit fetchurl libiconv; };
 in
 stdenv.mkDerivation (finalAttrs: ((mecab-base finalAttrs) // {
   pname = "mecab-nodic";