Don't request a TTY

The hardcoded paths are the one thing which has kept me from sing autogen.des regularly

CI setup.

Use SIGKILL which is sure to work.

We recognize only the most famous signals by name SIGTERM, SIGINT
and SIGKILL, if you want a special signal you will have to use "-15"
or whatever.

The primary reason for this is that there is still no portable API
for translating "SIGXXX" to an integer.

It used to be that bin/kill.c contained an array:

	const char *const sys_signame[NSIG] = {
		[0] =           "Signal 0",
		[SIGHUP] =      "HUP",
		[SIGINT] =      "INT",
		[SIGQUIT] =     "QUIT",
		[SIGILL] =      "ILL",
		[...]

BSD unix sensibly moved this into libc, to avoid duplicating
this all over the place, but Linux has not done that.

The right way to do this, would have been to have <signal.h>
contain a table:

	#ifdef SIGNAL_DOC(n,s,l)
	SIGNAL_DOC(1, "HUP", "Hangup")
	SIGNAL_DOC(2, "INT", "Interrupt")
	...
	#endif

That way nobody would ever need another #ifdef SIGFOO.

Anyway...

Rather than pointlessly add a semi-complete list of signals no
sensible person should ever use in a varnishtest (SIGWINCH anybody
?) we support the famous three by name, and the rest by number.

For epoll, we tolerate spurious reports, for all other waiters
we assert.

fixes #2117

0 bytes are not a bogus number

commit c457b965 was incomplete

This should fix #2128 for good

doc-fixes #2129

May be a preliminary solution should phk decide to do this differently.

Fixes #2128

Related to #2130

The otherwise recommended clock_get_time(SYSTEM_TIME) is about 40x
slower than mach_absolute_time() even after minimizing overhead by
retrieving the port right only once per process - see
https://github.com/nigoroll/varnish-cache/tree/macos_SYSTEM_CLOCK

So we revert to mach_absolute_time() which needs some scaling but
otherwise does the job. It is reported to halt on iOS devices when
sleeping, but even if anyone came up with the idea to sell varnish
over the app store, sleeping would probably need to be avoided in the
first place and otherwise the right way would probably be to adjust
the offset using pre/post sleep callbacks.

As MacOS should have been the last platform using the real clock
fallback for VTIM_mono, we now bail out at compile-time for any
platform we have overlooked.

Fixes #1899
Closes #2110

Ramp up from simple tokens to here documents.