Replay progress report

[Eric S. Raymond]

Still trying to get the peer structures set up properly in replay
mode.  It's pretty clear that a prerequisite for this is having the
DNS lookups done, and we don't want replay to depend on being able to
do DNS lookups.

So, my latest set of changes adds the capability to force synchronous
DNS lookup before the main loop gets started.  This is used in capture
mode to log the lookups.  Their captures look like this:

getaddrinfo 0.ubuntu.pool.ntp.org 198.55.111.5 1
getaddrinfo 1.ubuntu.pool.ntp.org 64.71.128.26 1
getaddrinfo 2.ubuntu.pool.ntp.org 2001:470:1:15b::5 1
getaddrinfo 3.ubuntu.pool.ntp.org 173.49.198.27 1
getaddrinfo ntp.ubuntu.com 2001:67c:1560:8003::c7 1

Replay mode picks these up from the capture, so it never actually
calls getaddrinfo.

That wasn't the last problem, alas.  Something's still going off-track
inside receive() in replay mode.  I'll fix it next year :-)
-- 
		<a href="http://www.catb.org/~esr/">Eric S. Raymond</a>

All governments are more or less combinations against the
people. . .and as rulers have no more virtue than the ruled. . .
the power of government can only be kept within its constituted
bounds by the display of a power equal to itself, the collected
sentiment of the people.
	-- Benjamin Franklin Bache, in a Phildelphia Aurora editorial 1794