Do not warn about an ununsed function, if it is marked with __attribute__((used)).

[cparser] / parsetest / designators2.c

#include <assert.h>

typedef struct blub {
        int i;
        char a[4];
} blub;

blub a = { .a[2] = 2, 3, .i = 23 };

int main(void)
{
        assert(a.a[2] == 2);
        assert(a.a[3] == 3);
        return 0;
}