address argument to atomic operation must be a pointer to non-const _Atomic type

Description

Hello! I'm the maintainer of php in MacPorts, and I noticed this build failure of php 8.2.0alpha2 and 8.2.0alpha1 on macOS 10.13 with Xcode 9.4.1 and its Apple clang 902.0.39.2:

Zend/zend_atomic.h:85:9: error: address argument to atomic operation must be a pointer to non-const _Atomic type ('const _Atomic(bool) *' invalid)
        return __c11_atomic_load(&obj->value, __ATOMIC_SEQ_CST);
               ^                 ~~~~~~~~~~~

Here is a full failed build log from macOS 10.13.

I also verified the problem on macOS 10.13 with Xcode 10.1 and its Apple clang 1000.11.45.5.

It also fails similarly on macOS 10.12, OS X 10.11, and OS X 10.10.

The build succeeds on macOS 10.14 with Xcode 10.3 and its Apple clang 1001.0.46.4 and on newer systems. Here is a full successful build log from macOS 10.14.

Curiously the build also succeeds on much older systems like OS X 10.9, OS X 10.8, and Mac OS X 10.7 with their older versions of Xcode and clang.

I see "c11" in the error message but I don't see -std=c11 being passed to the compiler. Thinking this might be a situation where certain older compilers would support whatever you're wanting to do if only you would ask the compiler to be in c11 mode, I tried adding -std=c11 on macOS 10.13 with Xcode 10.1 and its Apple clang 1000.11.45.5, and I also tried -std=gnu11, but neither of those changed the error.

php 8.1.7 and earlier don't have this problem.

PHP Version

8.2.0alpha2

Operating System

macOS 10.13.6

从 Zend/zend_atomic.h 开始，在报告中列出的受影响的 macOS 和 Apple clang 版本上重现 PHP 8.2 的构建。比较报告中的各个编译器版本之间原子操作的行为；当 PHP 能够在受影响的系统上成功构建，且不会导致较新和较旧配置出现回归时，工作即完成。