1) Finishedup my DPSRCS fixes from way back. Now any .h files will

1) Finishedup my DPSRCS fixes from way back.  Now any .h files will
   automatically be depended and stripped out of the SRCS line
   (I also left the external definition as well, in case of non-src
    dependencies)

2) Cleaned up some of the clean/cleandirs to have a more pleasing format
   (rm -f on every line rather than line-continuations)

3) Added Charles Hannum's dependency fixes for a cleaner make depend that
   works for both c/c++ files

4) Added default targets for (file.cc|cxx|C) -> file.o in the all
   affected make macros.  However, these as well as Charles c++
   dependency fixes are commented out so that groff won't be broken.
   I'll uncomment them after further testing on my box and seeing if
   groff should be modified rather than relying on gcc2 doing the right
   thing (subject to group vote)