Protect calls from macros

fix #918

include/boost/beast/websocket/impl/write.ipp

@@ -76,7 +76,7 @@ public:
     allocator_type
     get_allocator() const noexcept
     {
-        return boost::asio::get_associated_allocator(h_);
+        return (boost::asio::get_associated_allocator)(h_);
     }
 
     using executor_type = boost::asio::associated_executor_t<
@@ -85,7 +85,7 @@ public:
     executor_type
     get_executor() const noexcept
     {
-        return boost::asio::get_associated_executor(
+        return (boost::asio::get_associated_executor)(
             h_, ws_.get_executor());
     }