skypeforlinux: add gsettings schemas

cherry-picked and squashed from https://github.com/NixOS/nixpkgs/pull/44652

pkgs/applications/networking/instant-messengers/skypeforlinux/default.nix

···
-{ stdenv, fetchurl, dpkg, makeWrapper
+{ stdenv, fetchurl, dpkg
 , alsaLib, atk, cairo, cups, curl, dbus, expat, fontconfig, freetype, gdk_pixbuf, glib, glibc, gnome2, gnome3
-, gtk3, libnotify, libpulseaudio, libsecret, libv4l, nspr, nss, pango, systemd, xorg }:
+, gtk3, libnotify, libpulseaudio, libsecret, libv4l, nspr, nss, pango, systemd, wrapGAppsHook, xorg }:
 
 let
 
···
 
   inherit src;
 
-  buildInputs = [ dpkg makeWrapper ];
+  nativeBuildInputs = [
+    wrapGAppsHook
+    glib # For setup hook populating GSETTINGS_SCHEMA_PATH
+  ];
+
+  buildInputs = [ dpkg ];
 
   unpackPhase = "true";
   installPhase = ''
···
     done
 
     ln -s "$out/share/skypeforlinux/skypeforlinux" "$out/bin/skypeforlinux"
+
+    wrapProgram $out/bin/skypeforlinux \
+      --suffix XDG_DATA_DIRS : "$GSETTINGS_SCHEMAS_PATH"
+
 
     # Fix the desktop link
     substituteInPlace $out/share/applications/skypeforlinux.desktop \