Allow for parallel byte-compiling.

Allow for parallel byte-compiling.
(ELCFILES): New variable.
(.el.elc): Remove prerequisites from suffix rule.  Print a message.
(compile-first, compile-main, compile-last): New targets.
(compile-always): Simplify - delete .elc files, then `make compile'.

(compile-calc): Use glob rather than find.
($(lisp)/progmodes/cc-mode.elc): Use $@.