Add -e argument to xl console and pass to new escape_character argument
of libxl_console_exec.
Introduce a new API version to support this new argument and advertise
the new functionality in libxl.h
In libxl_console_exec, there are currently two call sites to execl,
which uses varargs, in order to support optionally passing
'start-notify-fd' to the console client. In order to support passing
the 'escape' argument optionally too, refactor to instead have a single
call site to execv, which has the same behavior but takes an array of
arguments.
If -e is not specified, --escape is not passed to the console client and
the existing value (^]) is used as a default.
Update the xl docs.
Signed-off-by: Peter Hoyes <Peter.Hoyes@arm.com>
Reviewed-by: Anthony PERARD <anthony.perard@citrix.com>