Handle C++11 lambda functions.

Handle C++11 lambda functions.

* lisp/progmodes/cc-engine.el (c-looking-at-inexpr-block): Enhance also to
handle C++ lambda functions.
(c-looking-at-c++-lambda-capture-list): New function.

* lisp/progmodes/cc-fonts.el (c-font-lock-declarations): Recognize the
parameter list of a lambda function and set `context' and
`c-restricted-<>-arglists' suitably for it.
(c-font-lock-c++-lambda-captures): New function.
(c-complex-decl-matchers): Insert c-font-lock-c++-lambda-captures into it.

* lisp/progmodes/cc-langs.el (c-pre-lambda-tokens, c-pre-lambda-tokens-re):
New language constants/variables.
(c-paren-nontype-kwds): Include "noexcept" in the C++ value.

* lisp/progmodes/cc-mode.el (c-fl-decl-start): Handle being in a C++ lambda
function capture list.