anchor.diff:    };
   
     meta = with lib; {
  +    description = "Source code editing widget for GTK";
       homepage = "https://wiki.gnome.org/Projects/GtkSourceView";
  -    platforms = with platforms; linux ++ darwin;
  -    license = licenses.lgpl21;
  +    platforms = platforms.unix;
  +    license = licenses.lgpl21Plus;
       maintainers = teams.gnome.members;
     };
   }
  
positive.code: { lib, stdenv, fetchurl, fetchpatch, pkg-config, atk, cairo, glib, gtk3, pango, fribidi, vala
  , libxml2, perl, gettext, gnome3, gobject-introspection, dbus, xvfb_run, shared-mime-info
  , meson, ninja }:
  
  stdenv.mkDerivation rec {
    pname = "gtksourceview";
    version = "4.8.1";
  
    src = fetchurl {
      url = "mirror://gnome/sources/${pname}/${lib.versions.majorMinor version}/${pname}-${version}.tar.xz";
      sha256 = "0WPXG1/K+8Wx7sbdhB7b283dOnURzV/c/9hri7/mmsE=";
    };
  
    propagatedBuildInputs = [
      # Required by gtksourceview-4.0.pc
      gtk3
      # Used by gtk_source_language_manager_guess_language
      shared-mime-info
    ];
  
    outputs = [ "out" "dev" ];
  
    nativeBuildInputs = [ meson ninja pkg-config gettext perl gobject-introspection vala ];
  
    checkInputs = [ xvfb_run dbus ];
  
    buildInputs = [ atk cairo glib pango fribidi libxml2 ];
  
    patches = [
      ./4.x-nix_share_path.patch
  
      # fixes intermittent "gtksourceview-gresources.h: no such file" errors
  
negative.code:     })
    ];
  
    nativeBuildInputs = [
      meson
      ninja
      pkg-config
      gettext
      perl
      gobject-introspection
      vala
    ];
  
    buildInputs = [
      atk
      cairo
      glib
      pango
      fribidi
      libxml2
    ];
  
    propagatedBuildInputs = [
      # Required by gtksourceview-4.0.pc
      gtk3
      # Used by gtk_source_language_manager_guess_language
      shared-mime-info
    ];
  
    checkInputs = [
      xvfb_run
      dbus
    ];
  
    doCheck = stdenv.isLinux;
  
    checkPhase = ''
      runHook preCheck
  
      XDG_DATA_DIRS="$XDG_DATA_DIRS:${shared-mime-info}/share" \
      xvfb-run -s '-screen 0 800x600x24' dbus-run-session \
        --config-file=${dbus.daemon}/share/dbus-1/session.conf \
        meson test --no-rebuild --print-errorlogs
  
      runHook postCheck
    '';
  
    passthru = {
  