msvcirt: Share exceptions implementation with msvcp

[Piotr Caban]

On 05/26/15 07:41, Alexandre Julliard wrote:
> Please avoid as many ifdefs as possible. For instance, having extra
> enums or unexported functions doesn't do any harm, so there's no reason
> to make a special case for them.

Some of the exception classes depend on basic_string class that is not 
available in msvcirt. What's the preferred way of dealing with them? 
Should we ifdef them out or e.g. define fake
MSVCP_basic_string_char_ctor_cstr, MSVCP_basic_string_char_c_str and 
MSVCP_basic_string_char_dtor just to make it compile?