fix: missing build.rs

source/ports/rs_port2/crates/metacall-bindings/.gitignore

@@ -1 +1,2 @@
 /target
+!build.rs

source/ports/rs_port2/crates/metacall-bindings/build.rs

@@ -0,0 +1,29 @@
+use std::env;
+
+fn main() {
+    // When running tests from CMake
+    if let Ok(val) = env::var("PROJECT_OUTPUT_DIR") {
+        // Link search path to build folder
+        println!("cargo:rustc-link-search=native={val}");
+
+        // Link against correct version of metacall
+        match env::var("CMAKE_BUILD_TYPE") {
+            Ok(val) => {
+                if val == "Debug" {
+                    // Try to link the debug version when running tests
+                    println!("cargo:rustc-link-lib=dylib=metacalld");
+                } else {
+                    println!("cargo:rustc-link-lib=dylib=metacall");
+                }
+            }
+            Err(_) => {
+                println!("cargo:rustc-link-lib=dylib=metacall");
+            }
+        }
+    } else {
+        // When building from Cargo
+        println!("cargo:rustc-link-lib=dylib=metacall")
+    }
+}
+
+