coredump support

http://www.fsmware.com/xen/patches/050429/coredump.patch

This patch adds an interface to libxc to do a coredump of a domain. It also extends gdbserver to allow one to debug a coredump as if it were a permanently paused guest.

Then from a gdb with the symbols loaded it is the same as before:

(gdb) target remote ip:port

Assuming you've applied the previous ptrace patch, you'll have to do a trivial resolve in xc_ptrace.c because of the recent name changes.