HACK: xcode clang++16 does not support C++20 std::atomic_ref.

Author: evoskuil

include/bitcoin/database/impl/primitives/arrayhead.ipp

@@ -134,7 +134,9 @@ Link CLASS::at(size_t key) const NOEXCEPT
     {
         // Reads full padded word.
         const auto raw = ptr->data();
-        const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        // xcode clang++16 does not support C++20 std::atomic_ref.
+        ////const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        const auto& head = *pointer_cast<std::atomic<integer>>(raw);
         return head.load(std::memory_order_acquire);
     }
     else
@@ -162,7 +164,9 @@ bool CLASS::push(const Link& link, const Link& index) NOEXCEPT
     {
         // Writes full padded word (0x00 fill).
         const auto raw = ptr->data();
-        const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        // xcode clang++16 does not support C++20 std::atomic_ref.
+        ////const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        auto& head = *pointer_cast<std::atomic<integer>>(raw);
         head.store(link, std::memory_order_acq_rel);
     }
     else

include/bitcoin/database/impl/primitives/hashhead.ipp

@@ -132,7 +132,9 @@ inline Link CLASS::top(const Link& index) const NOEXCEPT
     if constexpr (Align)
     {
         // Reads full padded word.
-        const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        // xcode clang++16 does not support C++20 std::atomic_ref.
+        ////const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        const auto& head =* pointer_cast<std::atomic<integer>>(raw);
         return head.load(std::memory_order_acquire);
     }
     else
@@ -164,7 +166,9 @@ inline bool CLASS::push(const Link& current, bytes& next,
     if constexpr (Align)
     {
         // Writes full padded word (0x00 fill).
-        const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        // xcode clang++16 does not support C++20 std::atomic_ref.
+        ////const std::atomic_ref<integer> head(unsafe_byte_cast<integer>(raw));
+        auto& head = *pointer_cast<std::atomic<integer>>(raw);
         next = Link(head.exchange(current, std::memory_order_acq_rel));
     }
     else