rust/chg/build.rs

narrow: factor out logic to build ellipses related b2parts in separate fn

This will help us switch more cleanly to using wireprotocol commands instead of
using exchange.pull() which exchanges more things then required.

Differential Revision: https://phab.mercurial-scm.org/D6435

extern crate cc;

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