Bootstrap speed

[Stefan Monnier]

With the native compiler, I get the impression that the compilation from
`.el` to `.elc` files is faster but I also see that we spent an insane
amount of time in:

    ELC+ELN  emacs-lisp/macroexp.elc
    ELC+ELN  emacs-lisp/cconv.elc
    ELC+ELN  emacs-lisp/byte-opt.elc
    ELC+ELN  emacs-lisp/bytecomp.elc
    ELC+ELN  emacs-lisp/comp.elc
    ELC+ELN  emacs-lisp/comp-cstr.elc

right after the first dump.
I suspect this can be sped up significantly if we did something like:

    ELC  emacs-lisp/macroexp.elc
    ELC  emacs-lisp/cconv.elc
    ELC  emacs-lisp/byte-opt.elc
    ELC  emacs-lisp/bytecomp.elc
    ELC  emacs-lisp/comp.elc
    ELC  emacs-lisp/comp-cstr.elc
    ELN  emacs-lisp/macroexp.elc
    ELN  emacs-lisp/cconv.elc
    ELN  emacs-lisp/byte-opt.elc
    ELN  emacs-lisp/bytecomp.elc
    ELN  emacs-lisp/comp.elc
    ELN  emacs-lisp/comp-cstr.elc

Instead.


        Stefan