LibC: Implement C++ static guards

userspace/libraries/LibC/icxxabi.cpp

@@ -39,3 +39,26 @@ extern "C" void __cxa_finalize(void* f)
 		}
 	}
 };
+
+namespace __cxxabiv1
+{
+	using __guard = uint64_t;
+
+	extern "C" int __cxa_guard_acquire (__guard* g)
+	{
+		uint8_t* byte = reinterpret_cast<uint8_t*>(g);
+		uint8_t zero = 0;
+		return __atomic_compare_exchange_n(byte, &zero, 1, false, __ATOMIC_ACQUIRE, __ATOMIC_ACQUIRE);
+	}
+
+	extern "C" void __cxa_guard_release (__guard* g)
+	{
+		uint8_t* byte = reinterpret_cast<uint8_t*>(g);
+		__atomic_store_n(byte, 0, __ATOMIC_RELEASE);
+	}
+
+	extern "C" void __cxa_guard_abort (__guard*)
+	{
+		ASSERT_NOT_REACHED();
+	}
+}