How to hide warnings about ignored attributes in Xcode?

How can I disable the following warning in Xcode?

'packed' attribute ignored for field of type 'uchar' (aka 'unsigned char')

I browsed through the list of warning switches but couldn't find anything regarding this, also disabled pedantic warnings without success.

Solution

Use -Wignored-attributes

#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wignored-attributes"
your code
#pragma clang diagnostic pop