Partially correct fontification of "(b*3)", and the like, in C++ Mode

Partially correct fontification of "(b*3)", and the like, in C++ Mode

This problem is caused by the fundamental ambiguity in C++ between
argument declarations and initialisation clauses.

* lisp/progmodes/cc-fonts.el (c-font-lock-declarations): If we have an open
paren preceded by an arithmetic operator, we give this the context nil, not
'arglist.

* lisp/progmodes/cc-langs.el (c-arithmetic-operators, c-arithmetic-op-regexp):
New lang consts and vars.