add cargo runner support in order to work with cross

build.rs

@@ -0,0 +1,16 @@
+use std::env;
+use std::fs;
+use std::io::Write;
+use std::path;
+
+fn main() {
+    println!("cargo:rerun-if-changed=build.rs");
+
+    // env::ARCH doesn't include full triplet, and AFAIK there isn't a nicer way of getting the full triplet
+    // (see lib.rs for the rest of this hack)
+    let out = path::PathBuf::from(env::var_os("OUT_DIR").expect("run within cargo"))
+        .join("current_target.txt");
+    let default_target = env::var("TARGET").expect("run as cargo build script");
+    let mut file = fs::File::create(out).unwrap();
+    file.write_all(default_target.as_bytes()).unwrap();
+}

src/cargo.rs

@@ -132,12 +132,27 @@ impl CommandCargoExt for process::Command {
 pub(crate) fn cargo_bin_cmd<S: AsRef<str>>(name: S) -> Result<process::Command, CargoError> {
     let path = cargo_bin(name);
     if path.is_file() {
-        Ok(process::Command::new(path))
+        if let Some(runner) = cargo_runner() {
+            let runner_vec: Vec<_> = runner.split(" ").collect();
+            let mut cmd = process::Command::new(runner_vec[0]);
+            cmd.args(&runner_vec[1..]).arg(path);
+            Ok(cmd)
+        } else {
+            Ok(process::Command::new(path))
+        }
     } else {
         Err(CargoError::with_cause(NotFoundError { path }))
     }
 }
 
+pub(crate) fn cargo_runner() -> Option<String> {
+    let runner_env = format!(
+        "CARGO_TARGET_{}_RUNNER",
+        CURRENT_TARGET.replace("-", "_").to_uppercase()
+    );
+    std::env::var(runner_env).ok()
+}
+
 /// Error when finding crate binary.
 #[derive(Debug)]
 pub struct CargoError {
@@ -206,3 +221,6 @@ fn cargo_bin_str(name: &str) -> path::PathBuf {
         .map(|p| p.into())
         .unwrap_or_else(|| target_dir().join(format!("{}{}", name, env::consts::EXE_SUFFIX)))
 }
+
+/// The current process' target triplet.
+pub const CURRENT_TARGET: &str = include_str!(concat!(env!("OUT_DIR"), "/current_target.txt"));