class Gem::BasicSpecification

def contains_requirable_file? file
  if @ignored then
    return false
  elsif missing_extensions? then
    @ignored = true
    warn "Ignoring #{full_name} because its extensions are not built.  " +
      "Try: gem pristine #{name} --version #{version}"
    return false
  end
  have_file? file, Gem.suffixes
end