Unbreak "make lint" for programs and "make llib-l${LIB}.ln" for

Unbreak "make lint" for programs and "make  llib-l${LIB}.ln" for
libraries a little by not passing all of ${CFLAGS} to lint.  Pass
only options matching -[DIU]*.  The important -nostdinc option can't
be passed like I first thought because lint misinterprets as
"-n -o stdinc".  The unimportant -B* option can't be passed because
lint doesn't support it.  Otherwise, we pass the same options as
to mkdep, exept for a bug in the latter: -U* is not passed.  All
this depends on option args not being separated from option flags
by a space.