Macro-expand interpreted code during load.

Macro-expand interpreted code during load.
* src/lread.c (readevalloop): Call internal-macroexpand-for-load to perform
eager (load-time) macro-expansion.
* src/lisp.mk (lisp): Add macroexp.
* lisp/loadup.el: Load macroexp.  Remove hack.
* lisp/emacs-lisp/macroexp.el (macroexp--eval-if-compile): New function.
(macroexp--expand-all): Use it to get better warnings.
(macroexp--backtrace, macroexp--trim-backtrace-frame)
(internal-macroexpand-for-load): New functions.
(macroexp--pending-eager-loads): New var.
(emacs-startup-hook): New hack to replace one in loadup.el.
* lisp/emacs-lisp/cl-macs.el (cl--compiler-macro-list*)
(cl--compiler-macro-cXXr): Move to top, before they can be used.
(cl-psetf): Simplify.
(cl-defstruct): Add indent rule.