Make lf_queue<> compatible with atomic_wait

Utilities/lockless.h

@@ -307,14 +307,25 @@ public:
 		delete m_head.load();
 	}
 
-	void wait() noexcept
+	template <atomic_wait::op Flags = atomic_wait::op::eq>
+	void wait(std::nullptr_t null = nullptr) noexcept
 	{
 		if (m_head == nullptr)
 		{
-			m_head.wait(nullptr);
+			m_head.template wait<Flags>(nullptr);
 		}
 	}
 
+	const volatile void* observe() const noexcept
+	{
+		return m_head.load();
+	}
+
+	explicit operator bool() const noexcept
+	{
+		return m_head != nullptr;
+	}
+
 	template <typename... Args>
 	void push(Args&&... args)
 	{
@@ -414,6 +425,18 @@ public:
 	}
 };
 
+namespace atomic_wait
+{
+	template <typename T>
+	inline __m128i default_mask<lf_queue<T>> = _mm_cvtsi64_si128(-1);
+
+	template <typename T>
+	constexpr __m128i get_value(lf_queue<T>&, std::nullptr_t value = nullptr)
+	{
+		return _mm_setzero_si128();
+	}
+}
+
 // Concurrent linked list, elements remain until destroyed.
 template <typename T>
 class lf_bunch final