(calc-original-buffer): Declare it.

(calc-original-buffer): Declare it.
(calc-embed-outer-top, calc-embed-outer-bot, calc-embed-top)
(calc-embed-bot): New variables.
(calc-do-embedded, calc-embedded-mark-formula)
(calc-embedded-find-bounds, calc-embedded-duplicate)
(calc-embedded-new-formula, calc-embedded-make-info):
Replace variables outer-top, outer-bot, bot and top by declared
variables.
(calc-embed-prev-modes): New variable.
(calc-embedded-set-modes, calc-embedded-update): Replace variable
prev-modes with declared variable.
(calc-embed-vars-used): New variable.
(calc-embedded-make-info, calc-embedded-evaluate-expr)
(calc-embedded-update, calc-embedded-find-vars): Replace variable
vars-used by declared variable.