Add C++ support for --zig

Set `TARGET_CC` and `TARGET_CXX` to support both cc-rs and cmake-rs

src/compile.rs

@@ -111,7 +111,7 @@ fn compile_universal2(
 ///
 /// We create different files for different args because otherwise cargo might skip recompiling even
 /// if the linker target changed
-fn prepare_zig_linker(context: &BuildContext) -> Result<PathBuf> {
+fn prepare_zig_linker(context: &BuildContext) -> Result<(PathBuf, PathBuf)> {
     let target = &context.target;
     let arch = if target.cross_compiling() {
         if matches!(target.target_arch(), Arch::Armv7L) {
@@ -122,20 +122,24 @@ fn prepare_zig_linker(context: &BuildContext) -> Result<PathBuf> {
     } else {
         "native".to_string()
     };
-    let (zig_linker, cc_args) = match context.platform_tag {
+    let (zig_cc, zig_cxx, cc_args) = match context.platform_tag {
         // Not sure branch even has any use case, but it doesn't hurt to support it
-        None | Some(PlatformTag::Linux) => {
-            ("./zigcc-gnu.sh".to_string(), format!("{}-linux-gnu", arch))
-        }
+        None | Some(PlatformTag::Linux) => (
+            "./zigcc-gnu.sh".to_string(),
+            "./zigcxx-gnu.sh".to_string(),
+            format!("{}-linux-gnu", arch),
+        ),
         Some(PlatformTag::Musllinux { x, y }) => {
             println!("⚠️  Warning: zig with musl is unstable");
             (
                 format!("./zigcc-musl-{}-{}.sh", x, y),
+                format!("./zigcxx-musl-{}-{}.sh", x, y),
                 format!("{}-linux-musl", arch),
             )
         }
         Some(PlatformTag::Manylinux { x, y }) => (
             format!("./zigcc-gnu-{}-{}.sh", x, y),
+            format!("./zigcxx-gnu-{}-{}.sh", x, y),
             // https://github.com/ziglang/zig/issues/10050#issuecomment-956204098
             format!(
                 "${{@/-lgcc_s/-lunwind}} -target {}-linux-gnu.{}.{}",
@@ -150,32 +154,49 @@ fn prepare_zig_linker(context: &BuildContext) -> Result<PathBuf> {
         .join(env!("CARGO_PKG_NAME"))
         .join(env!("CARGO_PKG_VERSION"));
     fs::create_dir_all(&zig_linker_dir)?;
-    let zig_linker = zig_linker_dir.join(zig_linker);
+    let zig_cc = zig_linker_dir.join(zig_cc);
+    let zig_cxx = zig_linker_dir.join(zig_cxx);
+
+    let mut zig_cc_file = create_linker_script(&zig_cc)?;
+    writeln!(&mut zig_cc_file, "#!/bin/bash")?;
+    writeln!(&mut zig_cc_file, "python -m ziglang cc {}", cc_args)?;
+    drop(zig_cc_file);
+
+    let mut zig_cxx_file = create_linker_script(&zig_cxx)?;
+    writeln!(&mut zig_cxx_file, "#!/bin/bash")?;
+    writeln!(&mut zig_cxx_file, "python -m ziglang c++ {}", cc_args)?;
+    drop(zig_cxx_file);
+
+    Ok((zig_cc, zig_cxx))
+}
 
-    #[cfg(target_family = "unix")]
-    let mut custom_linker_file = OpenOptions::new()
+#[cfg(target_family = "unix")]
+fn create_linker_script(path: &Path) -> Result<std::fs::File> {
+    let custom_linker_file = OpenOptions::new()
         .create(true)
         .write(true)
         .truncate(true)
         .mode(0o700)
-        .open(&zig_linker)?;
-    #[cfg(not(target_family = "unix"))]
-    let mut custom_linker_file = File::create(&zig_linker)?;
-    writeln!(&mut custom_linker_file, "#!/bin/bash")?;
-    writeln!(&mut custom_linker_file, "python -m ziglang cc {}", cc_args)?;
-    drop(custom_linker_file);
-    Ok(zig_linker)
+        .open(path)?;
+    Ok(custom_linker_file)
+}
+
+#[cfg(not(target_family = "unix"))]
+fn create_linker_script(path: &Path) -> Result<File> {
+    File::create(path)
 }
 
 fn compile_target(
     context: &BuildContext,
     python_interpreter: Option<&PythonInterpreter>,
     bindings_crate: &BridgeModel,
 ) -> Result<HashMap<String, PathBuf>> {
-    let zig_linker = if context.zig && context.target.is_linux() {
-        Some(prepare_zig_linker(context).context("Failed to create zig linker wrapper")?)
+    let (zig_cc, zig_cxx) = if context.zig && context.target.is_linux() {
+        let (cc, cxx) =
+            prepare_zig_linker(context).context("Failed to create zig linker wrapper")?;
+        (Some(cc), Some(cxx))
     } else {
-        None
+        (None, None)
     };
 
     let mut shared_args = vec!["--manifest-path", context.manifest_path.to_str().unwrap()];
@@ -279,14 +300,18 @@ fn compile_target(
         // but forwarding stderr is still useful in case there some non-json error
         .stderr(Stdio::inherit());
 
-    if let Some(zig_linker) = zig_linker {
+    // Also set TARGET_CC and TARGET_CXX for cc-rs and cmake-rs
+    if let Some(zig_cc) = zig_cc {
         let env_target = context
             .target
             .target_triple()
             .to_uppercase()
             .replace("-", "_");
-        build_command.env(format!("{}_CC", env_target), &zig_linker);
-        build_command.env(format!("CARGO_TARGET_{}_LINKER", env_target), &zig_linker);
+        build_command.env("TARGET_CC", &zig_cc);
+        build_command.env(format!("CARGO_TARGET_{}_LINKER", env_target), &zig_cc);
+    }
+    if let Some(zig_cxx) = zig_cxx {
+        build_command.env("TARGET_CXX", &zig_cxx);
     }
 
     if let BridgeModel::BindingsAbi3(_, _) = bindings_crate {