Allow overriding the user and the config file paths for ntpd.
This also adds back --privsep-path from OpenNTPD, which really only
changes the installation instructions from 'make install', since ntpd
always uses the home directory of the ntpd user.
This borrows from the Darren's portable OpenNTPD and from OpenSSL, add
credits and a license.

I removed all of the code in fake-sensors, I don't think Henning wants
all the credit for an empty file.

This reworks a few of the common patches on Debian and Gentoo to be a
little nicer, and changes the patches to be per-fix rather than
per-file.

include naddy's patch for using the LOG_NTP syslog facility