Add reproduction for workspace build.rs failure

test.nix

@@ -139,6 +139,8 @@ rec
       doDoc = true;
     };
 
+  workspace-build-rs = naersk.buildPackage ./test/workspace-build-rs;
+
   # Fails with some remarshal error
   #servo = naersk.buildPackage
   #sources.servo

test/workspace-build-rs/Cargo.lock

@@ -0,0 +1,6 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+[[package]]
+name = "hello-from-generated-code"
+version = "0.1.0"
+

test/workspace-build-rs/Cargo.toml

@@ -0,0 +1,2 @@
+[workspace]
+members = [ "crate-a" ]

test/workspace-build-rs/crate-a/Cargo.toml

@@ -0,0 +1,6 @@
+# Cargo.toml
+# adapted from https://doc.rust-lang.org/cargo/reference/build-script-examples.html
+
+[package]
+name = "hello-from-generated-code"
+version = "0.1.0"

test/workspace-build-rs/crate-a/build.rs

@@ -0,0 +1,16 @@
+use std::env;
+use std::fs;
+use std::path::Path;
+
+fn main() {
+    let out_dir = env::var_os("OUT_DIR").unwrap();
+    let dest_path = Path::new(&out_dir).join("hello.rs");
+    fs::write(
+        &dest_path,
+        "pub fn message() -> &'static str {
+            \"Hello, World!\"
+        }
+        "
+    ).unwrap();
+    println!("cargo:rerun-if-changed=build.rs");
+}

test/workspace-build-rs/crate-a/src/main.rs

@@ -0,0 +1,7 @@
+// src/main.rs
+
+include!(concat!(env!("OUT_DIR"), "/hello.rs"));
+
+fn main() {
+    println!("{}", message());
+}