replace "this this" by "like this"

- add closefrom fallback for OS X / Linux systems, extracted from sudo,
but without the optimized versions, since they cannot work in a
chroot environment (and we're not performance critical here.)
- enable detecting libtls
- conditionally enable https constraint support

Layout build machinery closer to LibreSSL to make code sharing easier.
Split the big Makefile.am into src/compat.

This could come back some other time, for now its just an arbitrary
difference with upstream.

These do not exist on all systems in sys/cdefs.h, and they are unneeded
since the header is being used privately anyway.

Thanks to @chneukirchen for the suggestion.

Make a copy of __progname on start to avoid setproctitle clobbering it
later. Check if the OS supports __progname and emulate if unavailable.
- from OpenSSH.
Thanks to Paul B. Henson for reporting the setproctitle emulation issue
and Jonas 'Sortie' Termansen for suggesting __progname emulation.

Add a post-install check to ensure that PRIVSEP_PATH is really empty.

Due to some circular dependencies on Solaris, this needs to be defined
as a macro. We should just remove SA_LEN usage here next.

Make them a little more readable.

Fixes #3, thanks to @gitisihara for providing the initial patch and
testing.

Handle 'NULL', emit the program name.

reported by Loganaden Velvindron

update manpage and add more fatal logging

Call the compat code and select the correct emulation mode.
Remove the string encoding support, since we have fixed inputs for the
title string.

If sa_family is not set, sa_len should be zero.

- add OS X privsep user creation instructions from jasper@
- update install instructions to be the same everywhere
- remove outdated compiler flags

which is convenient, since it is exactly what we need.

There is no standard SIN_LEN, unlike SIN6_LEN.

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.

As long as autoconf requires an AUTHORS file, might as well use it.
Refer to the public commit logs for all contributors - that's what
they're for.

This makes it easier to see what is supported by each OS, and to improve
them individually.

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