C++ Mode: recognize brace blocks without the hitherto required = sign

C++ Mode: recognize brace blocks without the hitherto required = sign

* lisp/progmodes/cc-engine.el (c-looking-at-or-maybe-in-bracelist): Add code
to recognize a literal brace expression following an array declaration for
C++.
(c-looking-at-inexpr-block): Replace c-symbol-chars with c-symbol-char-key,
fixing a coding error.