Don't use char as an 8-bit type for %I8 if its size is not 8-bits. #215
Description
Our MSVC specifier support code currently assumes that char has 8 bits. While that's very common - it is not actually mandatory. So, when that's not the case, let's not use it for %I8 and just assume there is no 8-bit type we can use (and drop support for that specifer).