std::wstring support about x2struct HOT 3 OPEN

struct MYSTRUCT
{
    std::wstring content;
    XTOSTRUCT(O(content))
};

Failed to build doe to a x_struct_to_str function not found.
Replacing the wstring to string can pass the build, but failed to process wide characters.

from x2struct.

https://stackoverflow.com/a/7154226/8364323

from x2struct.

will support later

from x2struct.