move (using repository copy) bootp{d,ef,gw,test} into a common hierarchy
with a libcommon - to stop unnecessary recompilation of the source.
add Makefile* to suit.

warnsify

use CPPFLAGS instead of CFLAGS

rcsid fascism

specify man pages the new way.

Move this to where the latest consensus indicates it should go.
Also, integrate some fixes from Christos.