Forbid declarations after label, case and default statements.

[cparser] / parsetest / shouldfail / missing.c

int test1(int a) {
        if (a > 3) {
                return 1;
        else {
                return 2;
        }
}

int test2(int a, int b) {
        return a ? 1 + : 2;
}

int test3(int b) {
        return (b + ;
}

int test4(int a) {
        return test2(a + , a);
}