Add __sync_get_arbiter.

libctru/include/3ds/synchronization.h

@@ -59,6 +59,12 @@ static inline bool __strex(s32* addr, s32 val)
 /// Performs an atomic swap operation.
 #define AtomicSwap(ptr, value) __atomic_exchange_n((u32*)(ptr), (value), __ATOMIC_SEQ_CST)
 
+/**
+ * @brief Retrieves the synchronization subsystem's address arbiter handle.
+ * @return The synchronization subsystem's address arbiter handle.
+ */
+Handle __sync_get_arbiter(void);
+
 /**
  * @brief Initializes a light lock.
  * @param lock Pointer to the lock.

libctru/source/synchronization.c

@@ -16,6 +16,11 @@ void __sync_fini(void)
 		svcCloseHandle(arbiter);
 }
 
+Handle __sync_get_arbiter(void)
+{
+	return arbiter;
+}
+
 void LightLock_Init(LightLock* lock)
 {
 	do