rust/hgcli/build.rs

rebase: when collapsing, p1 == dest, so use the former only

`dest` is the destination we're rebasing onto, which is always the
same as `p1` when using `--collapse`. This lets us simplify a bit.

Differential Revision: https://phab.mercurial-scm.org/D9073

// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

/*! Build script to integrate PyOxidizer. */

fn main() {
    if let Ok(config_rs) = std::env::var("DEP_PYTHONXY_DEFAULT_PYTHON_CONFIG_RS") {
        println!(
            "cargo:rustc-env=PYOXIDIZER_DEFAULT_PYTHON_CONFIG_RS={}",
            config_rs
        );
    } else {
        panic!("unable to find build artifacts generated by pyembed crate");
    }
}