Small Makefile cleanup mainly related to tags file generation

Small Makefile cleanup mainly related to tags file generation

* src/Makefile.in (abs_srcdir): New, set by configure.
(maintainer-clean): Remove pointless echo.  That should be in the
top-level Makefile, if anywhere.  Delete TAGS-LISP.
(extraclean): No s/ and m/ directories for some time.
(TAGS): Remove no-longer-defined S_FILE.
Pass absolute filenames to etags once more.
(TAGS-LISP, $(lwlibdir)/TAGS): Correctly pass ETAGS to sub-makes.
($(lwlibdir)/TAGS): Remove useless subshell, check cd return value.

* lisp/Makefile.in (lisptagsfiles1, lisptagsfiles2, lisptagsfiles3)
(lisptagsfiles4): Use absolute filenames again.
(TAGS, TAGS-LISP): Not everything needs to run in one line.
Remove all *loaddefs files, not just the first.  Remove esh-groups.
(maintainer-clean): Delete TAGS, TAGS-LISP.

* lwlib/Makefile.in (abs_srcdir): New, set by configure.
(ETAGS, ctagsfiles): New variables.
(TAGS): Use ETAGS, ctagsfiles.  Use absolute filenames again.