Message        variant struct or union is a language extension.

 Description    Declaring a member to be a variant_struct or
                variant_union is a language extension of HP C.  Other
                C compilers might not successfully compile a program
                that uses the extension.

 User Action    Consider using an anonymous struct or union (one
                without a tag or declarator) instead:  anonymous
                structs/unions are supported by HP C and some other
                vendors' C compilers.