x2goclient: move to qmake4Hook

pkgs/applications/networking/remote/x2goclient/default.nix

···
-{ stdenv, fetchurl, cups, libssh, libXpm, nxproxy, openldap, makeWrapper, qt4 }:
+{ stdenv, fetchurl, cups, libssh, libXpm, nxproxy, openldap, makeWrapper, qt4, qmake4Hook }:
 
 stdenv.mkDerivation rec {
   name = "x2goclient-${version}";
···
   };
 
   buildInputs = [ cups libssh libXpm nxproxy openldap qt4 ];
-  nativeBuildInputs = [ makeWrapper ];
+  nativeBuildInputs = [ makeWrapper qmake4Hook ];
 
   patchPhase = ''
      substituteInPlace Makefile \
···
        --replace "-o root -g root" ""
   '';
 
-  makeFlags = [ "PREFIX=$(out)" "ETCDIR=$(out)/etc" ];
+  preConfigure = ''
+    qmakeFlags="$qmakeFlags ETCDIR=$out/etc"
+  '';
 
   enableParallelBuilding = true;