From 36b5063e9ae341728412985736d658e8c90a31ae Mon Sep 17 00:00:00 2001
From: Alexander Novikov <novikov_alexander@live.ru>
Date: Thu, 6 Aug 2026 17:33:20 +0200
Subject: [PATCH] Force-include arm_acle.h on aarch64 macOS to work around Qt
 qyieldcpu.h

Qt's qyieldcpu.h calls the ACLE intrinsic __yield() under
__has_builtin(__yield) without including <arm_acle.h>. Apple clang 21
reports the builtin as available but makes the resulting implicit
declaration an error, so every translation unit reaching
<QtCore/qatomic.h> fails to compile.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
---
 meson.build | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/meson.build b/meson.build
index 41c9392d..f2a0175c 100644
--- a/meson.build
+++ b/meson.build
@@ -191,6 +191,18 @@ elif system == 'darwin'
   general_link_args += [
     '-mmacosx-version-min=10.15'
   ]
+
+  # Qt's qyieldcpu.h (through 6.9.x at least) calls the ACLE intrinsic
+  # __yield() under __has_builtin(__yield) without including
+  # <arm_acle.h>. Apple clang 21 reports the builtin as available but
+  # makes the resulting implicit declaration an error, so every
+  # translation unit that reaches <QtCore/qatomic.h> fails to compile.
+  # Force-including the ACLE header supplies the declaration.
+  if architecture == 'aarch64' and meson.get_compiler('cpp').has_header('arm_acle.h')
+    general_defines += [
+      '-include', 'arm_acle.h'
+    ]
+  endif
   
   feature_defines = [
     '-DHAVE_BZ2',