Run the debug CLI without Cargo loader paths

- Add the Rust target library directory to the Linux debug CLI rpath
- Test that the built CLI runs without `LD_LIBRARY_PATH`

crates/bds-cli/build.rs

@@ -0,0 +1,30 @@
+use std::{env, process::Command};
+
+fn main() {
+    println!("cargo:rerun-if-env-changed=RUSTC");
+
+    if env::var("CARGO_CFG_TARGET_OS").as_deref() != Ok("linux")
+        || env::var("PROFILE").as_deref() != Ok("debug")
+    {
+        return;
+    }
+
+    let rustc = env::var_os("RUSTC").unwrap_or_else(|| "rustc".into());
+    let target = env::var("TARGET").expect("Cargo must provide the build target");
+    let output = Command::new(rustc)
+        .args(["--target", &target, "--print", "target-libdir"])
+        .output()
+        .expect("query Rust target library directory");
+    assert!(
+        output.status.success(),
+        "rustc --print target-libdir failed: {}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+    let target_libdir =
+        String::from_utf8(output.stdout).expect("Rust target library directory must be UTF-8");
+
+    println!(
+        "cargo:rustc-link-arg-bin=bds-cli=-Wl,-rpath,{}",
+        target_libdir.trim()
+    );
+}

crates/bds-cli/tests/process.rs

@@ -8,6 +8,23 @@ fn cli(home: &std::path::Path, args: &[&str]) -> std::process::Output {
         .unwrap()
 }
 
+#[cfg(target_os = "linux")]
+#[test]
+fn built_cli_runs_without_cargo_loader_paths() {
+    let output = Command::new(env!("CARGO_BIN_EXE_bds-cli"))
+        .env_remove("LD_LIBRARY_PATH")
+        .arg("--help")
+        .output()
+        .unwrap();
+
+    assert!(
+        output.status.success(),
+        "{}",
+        String::from_utf8_lossy(&output.stderr)
+    );
+    assert!(String::from_utf8_lossy(&output.stdout).contains("rebuild"));
+}
+
 #[test]
 fn process_exit_codes_help_and_shared_state_roundtrip() {
     let root = tempfile::tempdir().unwrap();