gnome.gtkhtml: use enchant2

We expect gnome2.gtkhtml4 provides exactly the same thing as gnome.gtkhtml.

This applies 8696842 to this package as well.

pkgs/desktops/gnome/default.nix

···
 
   nautilus-python = callPackage ./misc/nautilus-python { };
 
-  gtkhtml = callPackage ./misc/gtkhtml { enchant = pkgs.enchant1; };
+  gtkhtml = callPackage ./misc/gtkhtml { enchant = pkgs.enchant2; };
 
   pomodoro = callPackage ./misc/pomodoro { };
 

pkgs/desktops/gnome/misc/gtkhtml/default.nix

···
-{ lib, stdenv, fetchurl, pkg-config, gtk3, intltool
+{ lib, stdenv, fetchurl, fetchpatch, autoreconfHook, pkg-config, gtk3, intltool
 , gnome, enchant, isocodes, gsettings-desktop-schemas }:
 
 stdenv.mkDerivation rec {
···
     sha256 = "ca3b6424fb2c7ac5d9cb8fdafb69318fa2e825c9cf6ed17d1e38d9b29e5606c3";
   };
 
+  patches = [
+    # Enables enchant2 support.
+    # Upstream is dead, no further releases are coming.
+    (fetchpatch {
+      name ="enchant-2.patch";
+      url = "https://aur.archlinux.org/cgit/aur.git/plain/enchant-2.patch?h=gtkhtml4&id=0218303a63d64c04d6483a6fe9bb55063fcfaa43";
+      sha256 = "f0OToWGHZwxvqf+0qosfA9FfwJ/IXfjIPP5/WrcvArI=";
+      extraPrefix = "";
+    })
+  ];
+
   passthru = {
     updateScript = gnome.updateScript { packageName = "gtkhtml"; attrPath = "gnome.gtkhtml"; };
   };
 
-  nativeBuildInputs = [ pkg-config intltool ];
+  nativeBuildInputs = [ autoreconfHook pkg-config intltool ];
   buildInputs = [ gtk3 gnome.adwaita-icon-theme
                   gsettings-desktop-schemas ];