* changes:
util.hh: Delete remaining file and clean up headers
util.hh: Move nativeSystem to local-derivation-goal.cc
util.hh: Move stuff to types.hh
util.cc: Delete remaining file
util.{hh,cc}: Move ignoreException to error.{hh,cc}
util.{hh,cc}: Split out namespaces.{hh,cc}
util.{hh,cc}: Split out users.{hh,cc}
util.{hh,cc}: Split out strings.{hh,cc}
util.{hh,cc}: Split out unix-domain-socket.{hh,cc}
util.{hh,cc}: Split out child.{hh,cc}
util.{hh,cc}: Split out current-process.{hh,cc}
util.{hh,cc}: Split out processes.{hh,cc}
util.{hh,cc}: Split out file-descriptor.{hh,cc}
util.{hh,cc}: Split out file-system.{hh,cc}
util.{hh,cc}: Split out terminal.{hh,cc}
util.{hh,cc}: Split out environment-variables.{hh,cc}
