`Warning: Ignoring un-named typedef that does not introduce a struct or enumeration type` for `__attribute__((fallthrough));` on null statement

[michael-schwarz]

Code that includes the fallthrough statement attribute (https://gcc.gnu.org/onlinedocs/gcc/Statement-Attributes.html) produces this unrelated warning.

int main() {
    int a =5;

    switch(a) {
        case 5:
            a = 7; ; __attribute__((__fallthrough__));
        default:
            a = 8;
    }

}

This is a low priority issue discovered during goblint/bench#16 and I opened it mostly such that we can refer to it when we see this error message.

[michael-schwarz]

Closed via 5bc7361