downgrade: if a compression is removed, consider that too For compression format variant, the result of `fromrepo()` and `fromconfig()` is not a boolean and we have to actually equate those to find change. Differential Revision: https://phab.mercurial-scm.org/D9693

fn main() {
    cc::Build::new()
        .warnings(true)
        .file("src/sendfds.c")
        .file("src/sighandlers.c")
        .compile("procutil");
}