Macos support

.gitmodules

@@ -1,6 +1,6 @@
 [submodule "libcsp"]
 	path = libcsp
-	url = https://github.com/xarantolus/libcsp.git
+	url = https://github.com/unexcellent/libcsp.git
 [submodule "libcsp-sys/mini-scanf"]
 	path = libcsp-sys/mini-scanf
 	url = https://github.com/MuratovAS/mini-scanf.git

build.rs

@@ -702,8 +702,36 @@ version 2.1 of the License, or (at your option) any later version.
     // On some systems libclang cannot locate GCC's built-in headers
     // (stddef.h, stdint.h, …) on its own. Ask the C compiler where they live
     // and forward that as a -isystem path to clang.
-    for gcc_include in gcc_builtin_include() {
-        builder = builder.clang_arg(format!("-isystem{gcc_include}"));
+    //
+    // NOT on macOS: `cc -print-file-name=include` returns the Xcode
+    // toolchain's clang builtin dir there, and mixing a second clang builtin
+    // dir into libclang's search breaks include_next chaining — both stdint.h
+    // copies share the __CLANG_STDINT_H guard, so the second one is skipped
+    // and the SDK's stdint.h (with the actual typedefs) is never reached.
+    // libclang finds its own builtin headers on macOS.
+    if env::var("CARGO_CFG_TARGET_OS").as_deref() != Ok("macos") {
+        for gcc_include in gcc_builtin_include() {
+            builder = builder.clang_arg(format!("-isystem{gcc_include}"));
+        }
+    }
+
+    // On macOS the system headers live in the SDK, not /usr/include, and
+    // libclang doesn't find the sysroot on its own — ask xcrun. A sysroot
+    // already provided via BINDGEN_EXTRA_CLANG_ARGS (e.g. a cross build)
+    // takes precedence since bindgen appends those args after these.
+    if env::var("CARGO_CFG_TARGET_OS").as_deref() == Ok("macos") {
+        if let Ok(output) = std::process::Command::new("xcrun")
+            .args(["--show-sdk-path"])
+            .output()
+        {
+            let sdk = std::str::from_utf8(&output.stdout)
+                .unwrap_or_default()
+                .trim()
+                .to_owned();
+            if !sdk.is_empty() {
+                builder = builder.clang_arg(format!("-isysroot{sdk}"));
+            }
+        }
     }
 
     // SocketCAN header is Linux-only — skip for embedded/non-Linux targets