macOS: fix crash when IOHIDDevice property is not a string (#573)

- fixed crash on macOS when AirPods are connected (reported to happen with some AirPods on some macOS version);

Author: slouken

mac/hid.c

@@ -376,7 +376,7 @@ static int get_string_property(IOHIDDeviceRef device, CFStringRef prop, wchar_t
 
 	buf[0] = 0;
 
-	if (str) {
+	if (str && CFGetTypeID(str) == CFStringGetTypeID()) {
 		CFIndex str_len = CFStringGetLength(str);
 		CFRange range;
 		CFIndex used_buf_len;