add support for macos version suffix

README.md

@@ -146,6 +146,22 @@ Provided you have no stripped the symbols from your binary built, on Linux you c
    2.28
    ```
 
+### Specify macOS version
+
+To build for a specific minimum macOS version, add that version as a suffix to the `--target` value:
+
+```bash
+cargo zigbuild --target aarch64-apple-darwin.13.0
+```
+
+This passes the version to `zig cc`, and sets `MACOSX_DEPLOYMENT_TARGET` to the same value for `rustc` and any C/C++ build scripts. It overrides a `MACOSX_DEPLOYMENT_TARGET` set in the environment.
+
+> [!NOTE]
+> By default `--target` for `*-apple-darwin` will have Zig build for its own default minimum macOS version. This version depends on the Zig release, and it is not the same as the one `rustc` uses. For example, Zig 0.16 defaults to macOS 13.0, while `rustc` defaults to 11.0 for `aarch64-apple-darwin`.
+
+> [!NOTE]
+> `MACOSX_DEPLOYMENT_TARGET` on its own is not enough. `zig cc` ignores it, so without the suffix the linked binary uses Zig's default version.
+
 ### Specify target CPU
 
 When cross-compiling for a CPU newer than the target's baseline — for example AWS Graviton (ARM Neoverse) instances — specify the target CPU via `RUSTFLAGS`, or you may hit hard-to-diagnose `Illegal instruction` (SIGILL, exit code 132) errors at runtime, or leave performance on the table:

src/zig/cargo_env.rs

@@ -199,6 +199,12 @@ impl Zig {
                 cmd.env("PKG_CONFIG_SYSROOT_DIR", sdkroot);
             }
 
+            if raw_target.contains("apple-darwin")
+                && let Some((_, version)) = raw_target.split_once('.')
+            {
+                cmd.env("MACOSX_DEPLOYMENT_TARGET", version);
+            }
+
             // Enable unstable `target-applies-to-host` option automatically
             // when target is the same as host but may have specified glibc version
             if host_target == parsed_target {

src/zig/wrapper.rs

@@ -541,7 +541,8 @@ fn zig_target_env(triple: &Triple) -> Environment {
 }
 
 /// Build the target triple to pass to `zig cc -target`, where `abi_suffix` is
-/// the glibc version including its leading dot (`.2.36`) or an empty string.
+/// the glibc or macOS version including its leading dot (`.2.36`, `.13.0`)
+/// or an empty string.
 fn zig_target_triple(
     rust_target: &str,
     triple: &Triple,
@@ -586,9 +587,9 @@ fn zig_target_triple(
             // Zig 0.10.0 switched macOS ABI to none
             // see https://github.com/ziglang/zig/pull/11684
             if *zig_version > semver::Version::new(0, 9, 1) {
-                format!("{arch}-macos-none{abi_suffix}")
+                format!("{arch}-macos{abi_suffix}-none")
             } else {
-                format!("{arch}-macos-gnu{abi_suffix}")
+                format!("{arch}-macos{abi_suffix}-gnu")
             }
         }
         OperatingSystem::Windows => {
@@ -771,7 +772,7 @@ mod tests {
     #[test]
     fn test_zig_target_triple() {
         let cases = [
-            // Rust target (with optional glibc suffix), zig version, zig target
+            // Rust target (with optional version suffix), zig version, zig target
             ("x86_64-unknown-linux-gnu", "0.15.2", "x86_64-linux-gnu"),
             (
                 "x86_64-unknown-linux-gnu.2.36",
@@ -805,6 +806,16 @@ mod tests {
             // zig 0.10 switched the macOS abi to none
             ("aarch64-apple-darwin", "0.15.2", "aarch64-macos-none"),
             ("aarch64-apple-darwin", "0.9.1", "aarch64-macos-gnu"),
+            (
+                "aarch64-apple-darwin.13.0",
+                "0.15.2",
+                "aarch64-macos.13.0-none",
+            ),
+            (
+                "x86_64-apple-darwin.10.15",
+                "0.15.2",
+                "x86_64-macos.10.15-none",
+            ),
             (
                 "aarch64-apple-ios-macabi",
                 "0.15.2",