rust/chg/build.rs

fastannotate: use sysstr to deal with some attributes

We are now Python3 only and attribute are always unicode string. So no needs to
managed them using bytes.

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