GCC 7, -Wimplicit-fallthrough warnings, and portable way to clear them?

Question

We are catching warnings from GCC 7 for implicit fall through in a switch statement. Previously, we cleared them under Clang (that\'s the reason for the comment seen below):

Answer 1

Clean C solution:

int r(int a) {
    switch(a) {
    case 0:
        a += 3;
    case 1:
        a += 2;
    default:
        a += a;
    }
    return a;
}

becomes:

int h(int a) {
    switch(a) {
    case 0:
        a += 3;
        goto one;
    case 1:
    one:
        a += 2;
        goto others;
    default:
    others:
        a += a;
    }
    return a;
}

EDIT: Moved the labels after case statements, as suggested by Stéphane Gourichon in comments, to see the fallthrough more easily.