Correct calculation of CC Mode's font-lock region.

Correct calculation of CC Mode's font-lock region.

* cc-mode.el (c-fl-decl-start): Renamed from c-set-fl-decl-start.
* Change
signature such that nil is returned when no declaration is found.
(c-change-expand-fl-region): Renamed from c-change-set-fl-decl-start.
This now also handles expanding the font lock region to whole lines.
(c-context-expand-fl-region): Renamed from c-context-set-fl-decl-start.
This now also handles expanding the font lock region to whole lines.
(c-font-lock-fontify-region): When a change font lock region is
spuriously enlarged to the beginning-of-line by jit-lock, fontify the
extra bit separately from the region calculated by CC Mode.
(c-extend-after-change-region): Explicitly apply 'fontified properties
to
the extended bits of the font lock region.

* cc-langs.el (c-before-font-lock-functions)
(c-before-context-fontification-functions): Use new names for existing
functions (see above).