jom: move to qmake4Hook

pkgs/os-specific/windows/jom/default.nix

···
-{ stdenv, fetchgit, qt48, flex, cmake }:
+{ stdenv, fetchgit, qt48, qmake4Hook, flex }:
 
 # At the time of committing this, the expression fails for me to cross-build in
 # both mingw32 and mingw64.
···
   };
 
   buildInputs = [ qt48 ];
-  nativeBuildInputs = [ flex /*cmake*/ ];
+  nativeBuildInputs = [ flex qmake4Hook ];
 
   QTDIR = qt48;
-  configurePhase = ''
-    qmake PREFIX=$out
-  '';
   
   crossAttrs = {
     # cmakeFlags = "-DWIN32=1 -DCMAKE_SYSTEM_NAME=Windows -DCMAKE_RC_COMPILER=${stdenv.cross.config}-windres";