From 53bd38b7c5d5dc43feced7cf76904fa5b788de0c Mon Sep 17 00:00:00 2001
From: Mads Marquart <mads@marquart.dk>
Date: Mon, 6 May 2024 07:56:41 +0200
Subject: [PATCH] iOS/tvOS/watchOS: Fix alloc w. large alignment on older
 versions

Tested on an old MacBook and the iOS simulator.
---
 library/std/src/sys/pal/unix/alloc.rs | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/library/std/src/sys/pal/unix/alloc.rs b/library/std/src/sys/pal/unix/alloc.rs
index af0089978ec..9938c0bac25 100644
--- a/library/std/src/sys/pal/unix/alloc.rs
+++ b/library/std/src/sys/pal/unix/alloc.rs
@@ -13,7 +13,13 @@ unsafe impl GlobalAlloc for System {
         if layout.align() <= MIN_ALIGN && layout.align() <= layout.size() {
             libc::malloc(layout.size()) as *mut u8
         } else {
-            #[cfg(target_os = "macos")]
+            // `posix_memalign` returns a non-aligned value if supplied a very
+            // large alignment on older versions of Apple's platforms (unknown
+            // exactly which version range, but the issue is definitely
+            // present in macOS 10.14 and iOS 13.3).
+            //
+            // <https://github.com/rust-lang/rust/issues/30170>
+            #[cfg(target_vendor = "apple")]
             {
                 if layout.align() > (1 << 31) {
                     return ptr::null_mut();