Create generated lisp files before main loaddefs.el

Create generated lisp files before main loaddefs.el

This should improve reproducibility of lisp/loaddefs.el.
* lisp/Makefile.in (gen-lisp): New phony target.
($(lisp)/loaddefs.el, compile-main): Depend on gen-lisp.
* src/Makefile.in ($(leimdir)/leim-list.el): Depend on all of ../leim.
* lisp/cedet/semantic.el (semantic-mode):
* lisp/cedet/semantic/fw.el (top-level):
* lisp/emacs-lisp/eieio-core.el (top-level):
Robustify to generated input files maybe not yet existing.