Makefile: Changed proto: target to not include c files not used currently.

Makefile: Changed proto: target to not include c files not used currently.
          Caused proto.h to be from a sorted list of C files.
arcfour.h: Added prototypes.
client.c: Added username%password in environment patch from John Blair <jdblair@frodo.tucc.uab.edu>
loadparm.c: Added username manipulation code from Peter McCool [SMTP:peter@qimr.edu.au]
username.c: Added username manipulation code from Peter McCool [SMTP:peter@qimr.edu.au]
mkproto.awk: Added arc4_key type.
proto.h: Updated & sorted.
Jeremy (jallison@whistle.com)
(This used to be commit 97ed4fea67095dfb83227e7b5fffc236ff277e02)