Makefile: add elint to compilation methods, ensure *.elc files exist after compilation
* lisp/Makefile: Add targets `slint3´ (one Emacs process for all
sources) and `slint4´ (one Emacs instance for each source) using
ELINTL and ELINTF to lint lisp files. Split out compile actions
into internal targets and implement `compile-*´ targets in terms of
these internal targets. Follow all targets that do not
procude *.elc files with `dirall´ so that the *.elc files exist at
the end of compilation.
* default.mk: Add configuration variables ELINTL and ELINTF.
* targets.mk: Add ELINTL and ELINTF to CONF_CALL.