the beginnings of a new scheme I've working on to allow an easier

the beginnings of a new scheme I've working on to allow an easier
head/tng merge.

It goes something like this:

- headers from tng get copied over one at a time

- the old headers get renamed to *_old.h

- server side code that used the old headers gets a
  #define OLD_NTDOMAIN 1
  #undef OLD_NTDOMAIN
  at the start and end of the code

- mkproto.awk recognises these special defines and does magic stuff so
  that each .c file sees the right headers

- we start moving the rpc client libraries from tng to head.

if this goes OK then, in theory, we should be able to move the client
side rpc code from tng to head without disturbing the existing head
server side code. Then when that works we can consider merging the
server side.

it remains to be seen if this scheme will work. So far I've moved
rpc_samr.h and don't seem to have broken anything.

Note this this is still a very delicate operation, as at every step of
the way I want to keep head fully functional. Please don't take part
unless you discuss it with me first.
(This used to be commit f76c037255a6a79d11bec65e863e009a41a4f0fd)