readonly proc cxx_source (X) is
  local cxxfile = X&".cxx"
  local objfile = X&".o"
  %exec("echo $PWD")
  if stale(objfile,cxxfile)
    exec("cd",path(),"; g++ -I.. -c -o",objfile,cxxfile)
  end
  import_obj(X)
  %unlink_file(path()&SL&objfile)
end