* lisp/calc/calc-alg.el: Use lexical-binding and silence warnings

* lisp/calc/calc-alg.el: Use lexical-binding and silence warnings

* lisp/calc/calc-alg.el: Use lexical-binding and silence warnings.
(math-defsimplify): Let-bind 'expr' instead of math-simplify-expr.
Adjust all users.
(math-simplify-expr): Don't declare any more.
(math--simplify-divide-expr): New dynbound var.
(math-simplify-divide): Bind it when needed.
(math-simplify-divisor): Use it instead of math-simplify-expr.
(math-simplify-divisor): Only bind math-simplify-divisor-[nd]over
around the calls to math-simplify-one-divisor.
(math-expr-subst, math-is-polynomial): Don't use dynbound vars as
formal arguments.
(math-polynomial-base): Move binding of math-poly-base-pred.
Don't bind math-poly-base-top-expr any more...
* lisp/calc/calc-poly.el (math-total-polynomial-base): Bind it here instead!

* lisp/calc/calc-units.el: Use lexical-binding and silence warnings.
Adjust to the new 'expr' name in math-defsimplify.
(math-find-base-units, math-to-standard-units, math-convert-units):
Don't use dynbound vars as formal arguments.
(math-simplify-expr): Don't declare any more.