Use bsd.subdir.mk for building subdirectories.
Don't forget to remove x.cc and x.C when using SHAREDSTRINGS.
Make ${PROG} always depend on ${LIBCRT0}.
Don't duplicate code between cleandir and clean.
Move tags target to bsd.dep.mk.
Move STRIP to bsd.own.mk.
Remove redundant definitions of {BIN,MAN}{DIR,GRP,OWN,MODE}.
Move {LIB,DOC}{DIR,GRP,OWN,MODE} defaults to bsd.own.mk.
deqn, and dtbl.
Fixed make clean to remove the man pages (Bill fixed this in the distribution,
but not in the original source)
Changed install to leave the original file around, by using 'cp' instead of
'mv'. "install -c ..."