CC Mode: make c-display-defun-name work with a pointer return type.

CC Mode: make c-display-defun-name work with a pointer return type.

Fixes bug #32403.

* lisp/progmodes/cc-cmds.el (c-in-function-trailer-p): No longer insist on
c-beginning-of-decl-1 returning 'same.
(c-where-wrt-brace-construct): Tighten up the test for looking at a symbol by
excluding keywords.  When point is after a }, do not return 'at-function-end
for a struct/union/class/...
(c-defun-name-1): Considerably simplify, by amalgamating the two cond arms
which find structs etc., and by using functions like c-forward-declarator
rather than the faulty analysis of the source by hand.