[C++] sizeof with complex types

[petr-bauch]

The types from complex.h seem to be parsed in other contexts, e.g.

bar<double _Complex>();
float _Imaginary ** c;

But the same types are refused by the parser when given to sizeof operator, e.g.

std::size_t double_size = sizeof(double _Complex);

[codinuum]

The latter context within sizeof is different from the former, although both contexts allow types and expressions to occur. We hope c1a2764 fix the problem.

[petr-bauch]

Works without problems. Thanks a lot.