- 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.

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.

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

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

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

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.

Well, support may be too concrete of a term. There is a lot that is
missing in OS X, and not everything can be implemented with portability
shims. The time APIs in OS X seem to have frozen with NeXTSTEP and never
advanced with POSIX.

First attempt at building a new OpenNTPD portable project, based on the
latest OpenBSD source.