diff --git a/xtask/Cargo.toml b/xtask/Cargo.toml
index 882de747..920c0026 100644
--- a/xtask/Cargo.toml
+++ b/xtask/Cargo.toml
@@ -3,6 +3,7 @@ name = "xtask"
 version = "0.1.0"
 edition = "2021"
 publish = false
+build = "build.rs"
 
 [lints]
 workspace = true
diff --git a/xtask/build.rs b/xtask/build.rs
new file mode 100644
index 00000000..6fdc47bf
--- /dev/null
+++ b/xtask/build.rs
@@ -0,0 +1,7 @@
+fn main() {
+	println!(
+		"cargo:rustc-env=TARGET_PLATFORM={}",
+		&std::env::var("TARGET").unwrap()
+	);
+	println!("cargo:rerun-if-changed-env=TARGET");
+}
diff --git a/xtask/src/main.rs b/xtask/src/main.rs
index 49571efb..e21533c6 100644
--- a/xtask/src/main.rs
+++ b/xtask/src/main.rs
@@ -16,7 +16,7 @@ enum Opts {
 		callgrind: bool,
 		#[arg(long)]
 		cachegrind: bool,
-		#[arg(long, default_value = "x86_64-unknown-linux-gnu")]
+		#[arg(long, default_value = env!("TARGET_PLATFORM"))]
 		target: String,
 		args: Vec<String>,
 	},
@@ -26,9 +26,13 @@ enum Opts {
 		#[arg(long)]
 		fix: bool,
 	},
+	/// Build and run test file from `bindings/c`
 	TestCBindings {
-		#[arg(long, default_value = "x86_64-unknown-linux-gnu")]
+		#[arg(long, default_value = env!("TARGET_PLATFORM"))]
 		target: String,
+		/// Which bindings file to build and run
+		#[arg(long, default_value = "libjsonnet_test_file")]
+		test_file: String,
 		args: Vec<String>,
 	},
 }
@@ -78,7 +82,11 @@ fn main() -> Result<()> {
 			cmd!(sh, "cargo fmt {fmt_check...}").run()?;
 			Ok(())
 		}
-		Opts::TestCBindings { target, args } => {
+		Opts::TestCBindings {
+			target,
+			test_file,
+			args,
+		} => {
 			cmd!(
 				sh,
 				"cargo build -p libjsonnet --target={target} --release --no-default-features --features=interop-common,interop-threading"
@@ -86,7 +94,6 @@ fn main() -> Result<()> {
 			.run()?;
 			let built = format!("./target/{target}/release/libjsonnet.a");
 			let c_bindings = "./bindings/c/";
-			let test_file = "libjsonnet_test_file";
 			cmd!(sh, "cp {built} {c_bindings}").run()?;
 			sh.change_dir(c_bindings);