Xen 4.2 added to pkgsrc

[jnemeth%victoria.tc.ca@localhost (John Nemeth)]

     I've just committed sysutils/xenkernel42 and sysutils/xentools42.
They have had fairly extensive testing, but they are just initial
commits.  I've added them so that people can test them, break them,
improve them, etc.

     Note that xm/xend is deprecated but they do still work.  xl is
working in this version.  But, I've only tested it with file backed
vbds.  I haven't tested it with LVM or raw partitions.

     Major things that don't work yet are HVM and grant tables.  The
issue with HVM is that Qemu wasn't compiling, and I just commented it
out in order to move forward.  The issue with grant tables is that it
appears that the interface has changed and I haven't fully adapted the
code.

     So, have at it.  Let me know what breaks.  Patches would be
greatly appreciated (or just commit if you have cvs access).
Otherwise, I need enough details on what breaks in order to
duplicate/fix the problem.

     One thing to note is that Xen 4.3.0rc1 was released a week ago.
This raises the question of whether to spend a lot of time working on
improving the Xen 4.2 packages, or switch to starting work on the Xen
4.3 packages?  Any thoughts on this question?