Explicitly use WSASocketW, as WSASocketA has been deprecated.

asio/include/asio/detail/impl/socket_ops.ipp

diff --git a/asio/include/asio/detail/impl/socket_ops.ipp b/asio/include/asio/detail/impl/socket_ops.ipp
index 711ec73..a19c46d 100644
--- a/asio/include/asio/detail/impl/socket_ops.ipp
+++ b/asio/include/asio/detail/impl/socket_ops.ipp
@@ -1358,7 +1358,7 @@
 {
   clear_last_error();
 #if defined(ASIO_WINDOWS) || defined(__CYGWIN__)
-  socket_type s = error_wrapper(::WSASocket(af, type, protocol, 0, 0,
+  socket_type s = error_wrapper(::WSASocketW(af, type, protocol, 0, 0,
         WSA_FLAG_OVERLAPPED), ec);
   if (s == invalid_socket)
     return s;