Add support for kqueue by using the patches written by Dmitry Matveev during
the Google Summer of Code 2011 program.  Congratulations, Dmitry!  :-)

This comes in the form of a new 'kqueue' build-time option.  This should NOT
be an option, but it is for two reasons:
- I consider this still experimental for it to be enabled on everyone's
  machines, and the code is not "official".
- The patch requires us to run automake/autoconf during the pre-configure
  stage, and I don't want to add these dependencies on the default package
  build.
When these patches get integrated upstream, we can get rid of the option
altogether.

Also note that I had to backport some of our custom changes to Makefile.in
files and some to configure to the original Makefile.am files and
configure.ac.  This is to prevent our custom patches from being lost during
the automake/autoconf invocations we now do when 'kqueue' is enabled.

Bump PKGREVISION to 1.

(jmmv)