Fontify C++ for loop variable as variable, even when followed by parentheses

Fontify C++ for loop variable as variable, even when followed by parentheses

In the following: "for (auto *Friend : Class->friends()) {", "Friend" was
getting fontified as a function, due to insufficient checking of the tokens
between it and "()".

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

* lisp/progmodes/cc-engine.el (c-forward-declarator): After finding a putative
declarator's identifier, check for a ":" token inside a for's parentheses, and
abort the search for "(" if this is found.