Error handling in the new C++ parser

[Mark Mitchell]

> There seems to be no effort to skip to a sychronizing token
> (like ';' or ')') after a normal syntax error, like the old bison
> parser did.

It does that when it wants to do that.

There's no need to attempt immediately recovery after missing one
required token; we can wait util it's convenient.

Look for functions with names like cp_parser_skip* to find places where
we skip ahead until something sensible shows up.

I'm sure the error recovery can be improved, but it does OK most of
the time.

-- 
Mark Mitchell                mark@codesourcery.com
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