Fontify bitfield declarations properly.

cc-langs.el (c-has-bitfields): New lang variable.
(c-symbol-chars): Now exported as a lang variable.
(c-not-primitive-type-keywords): New lang variable.

cc-fonts.el (c-font-lock-declarations): Jump over the QT keyword "more"
to prevent "more slots: ...." being spuriously parsed as a bitfield
declaraion.

cc-engine.el (c-beginning-of-statement-1): Refactor and enhance to handle
bitfield declarations.
(c-punctuation-in): New function.
(c-forward-decl-or-cast-1): Enhance CASE 3 to handle bitfield
declarations properly.