rust/chg/build.rs

check-commit: use raw string for regular expression

Avoids SyntaxWarning on Python 3.8.

Differential Revision: https://phab.mercurial-scm.org/D5824

extern crate cc;

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