chore: fix windows

Author: achingbrain

include/rtc/global.hpp

@@ -34,7 +34,7 @@ RTC_CPP_EXPORT void InitLogger(LogLevel level, LogCallback callback = nullptr);
 RTC_CPP_EXPORT void Preload();
 RTC_CPP_EXPORT std::shared_future<void> Cleanup();
 
-RTC_CPP_EXPORT struct UnhandledStunRequest {
+struct UnhandledStunRequest {
 	optional<std::string> localUfrag;
 	optional<std::string> remoteUfrag;
 	std::string address;