patch: add hint about mangled whitespace on bad patch
One of the most common reasons that a patch doesn't apply is because
its whitespace has been mangled (e.g. by their mail client or though
copy&paste). Let's provide a hint about that.
Differential Revision: https://phab.mercurial-scm.org/D11825
fn main() {
cc::Build::new()
.warnings(true)
.file("src/sendfds.c")
.file("src/sighandlers.c")
.compile("procutil");
}