From f63b1b1be6ac59862ff9dd433f639324d19c4866 Mon Sep 17 00:00:00 2001
From: KaiTomotake <kaitomotake@gmail.com>
Date: Sat, 17 Jan 2026 23:07:45 +0900
Subject: [PATCH] add 'environ' variable

Add the environ variable to unix/mod.rs.

add aarch64_macos_15_5_or_newer cfg
---
 build.rs                  | 15 +++++++++++++++
 libc-test/semver/unix.txt |  1 +
 src/unix/mod.rs           |  5 +++++
 3 files changed, 21 insertions(+)

diff --git a/build.rs b/build.rs
index cbebca6207f2a..cba29c0d7508f 100644
--- a/build.rs
+++ b/build.rs
@@ -31,6 +31,7 @@ const ALLOWED_CFGS: &[&str] = &[
     // Corresponds to `_REDIR_TIME64` in musl
     "musl32_time64",
     "vxworks_lt_25_09",
+    "aarch64_macos_15_5_or_newer",
 ];
 
 // Extra values to allow for check-cfg.
@@ -65,6 +66,20 @@ fn main() {
     let target_ptr_width = env::var("CARGO_CFG_TARGET_POINTER_WIDTH").unwrap_or_default();
     let target_arch = env::var("CARGO_CFG_TARGET_ARCH").unwrap_or_default();
 
+    println!("cargo:rerun-if-env-changed=MACOSX_DEPLOYMENT_TARGET");
+
+    if target_os == "macos" && target_arch == "aarch64" {
+        if let Ok(deployment) = env::var("MACOSX_DEPLOYMENT_TARGET") {
+            let mut it = deployment.split('.');
+            let major = it.next().and_then(|x| x.parse::<u32>().ok()).unwrap_or(0);
+            let minor = it.next().and_then(|x| x.parse::<u32>().ok()).unwrap_or(0);
+
+            if (major, minor) >= (15, 5) {
+                set_cfg("aarch64_macos_15_5_or_newer");
+            }
+        }
+    }
+
     // The ABI of libc used by std is backward compatible with FreeBSD 12.
     // The ABI of libc from crates.io is backward compatible with FreeBSD 12.
     //
diff --git a/libc-test/semver/unix.txt b/libc-test/semver/unix.txt
index 052c24178dfcc..ae447cc7627e0 100644
--- a/libc-test/semver/unix.txt
+++ b/libc-test/semver/unix.txt
@@ -505,6 +505,7 @@ dlopen
 dlsym
 dup
 dup2
+environ
 execl
 execle
 execlp
diff --git a/src/unix/mod.rs b/src/unix/mod.rs
index f5f8d954fdadf..fae6cef059f23 100644
--- a/src/unix/mod.rs
+++ b/src/unix/mod.rs
@@ -2429,3 +2429,8 @@ cfg_if! {
         // Unknown target_os
     }
 }
+
+extern "C" {
+    #[cfg(not(aarch64_macos_15_5_or_newer))]
+    pub static mut environ: *mut *mut crate::c_char;
+}