Patches from Akim Demaille <akim@epita.fr>.
* config.sub (version): Rename from this ..
(timestamp): .. to this.
(usage): Replace --version with --time-stamp. Add additional help
and copyleft notice.
(time-stamp-start): Replace with "timestamp=".
* config.guess (version): Rename from this ..
(timestamp): .. to this.
(usage): Replace --version with --time-stamp. Add additional help
and copyleft notice.
(CC_FOR_BUILD): Rework this logic.
(time-stamp-start): Replace with "timestamp=".