More Adam stuff:

More Adam stuff:
+ lib/mlib.c, include/dpkg.h.in: make do_fd_copy even more modular
+ dpkg-deb/{build.c,extract.c,info.c}, lib/showcright.c,
  main/{enquiry.c,filesdb.c}: updated for new do_fd_copy routines
+ main/{archives,[ch],main/processarc.c}: use fds instead of streams
  so we don't mix fd and stream-based IO which can cause havoc