We've brought this up a few times, but I suppose we might as well drop
1.8 support in a major version change.
We may still maintain unicorn 4.x for 1.8 users indefinitely; after all,
we only accepted a patch for 1.8.6 compatibility less than a year
ago(!)[1]. So I'll still feel a _little_ bad for dropping 1.8 :x
One big reason for this is it looks like Ruby will move towards
deprecating old Data_* macros for superior (1.9+-only) TypedData_*
macros in the next few years[2]. The theme for unicorn 5 is mostly
dropping old, unused crap anyways; and not gaining new bloat.
Worst case is we support 1.8 and avoid deprecation warnings through
the use of ifdefs in the HTTP parser, but I'm no fan of ifdefs.
[1] commit 7e9e4c740aba24096f768f578779dc1053cb8b70
(construct listener_fds Hash in 1.8.6 compatible way)
[2] http://svn.ruby-lang.org/cgi-bin/viewvc.cgi?view=revision&revision=47717
This is due to type-checking issues like
https://bugs.ruby-lang.org/issues/10296
