Fix problems in CC Mode with " being entered into a comment at EOB.
* lisp/progmodes/cc-engine.el (c-full-lit-near-cache): Amend the definition such that an element's END element will be nil if the pertinent literal is open at EOB. (c-full-pp-to-literal): Before setting the aforementioned END element, check that we're no longer in a literal. (c-literal-limits): When c-full-pp-to-literal returns a list with a nil END element, replace this by (point-max) to keep the interface of c-literal-limits unchanged. * lisp/progmodes/cc-mode.el (c-after-change-mark-abnormal-strings): Having found a string quote, check it is not inside an unterminated comment (i.e. one at EOB).