Fix it

Author: uNetworkingAB

src/HttpParser.h

@@ -41,7 +41,13 @@ namespace uWS {
 static const unsigned int MINIMUM_HTTP_POST_PADDING = 32;
 static void *FULLPTR = (void *)~(uintptr_t)0;
 
-static const size_t MAX_FALLBACK_SIZE = std::max<size_t>((size_t) atoi(getenv("UWS_HTTP_MAX_HEADERS_SIZE")), 1024 * 4);
+/* STL needs one of these */
+template<typename T>
+std::optional<T> maybeify(T *ptr) {
+    return ptr ? ptr : std::nullopt;
+}
+
+static const size_t MAX_FALLBACK_SIZE = atoi(maybeify(getenv("UWS_HTTP_MAX_HEADERS_SIZE")).value_or("4096"));
 
 struct HttpRequest {