Windows: Don't freeze the UI thread for a sec while launching a URL

Windows/main.cpp

@@ -133,7 +133,12 @@ static double g_lastKeepAwake = 0.0;
 static constexpr double ACTIVITY_IDLE_TIMEOUT = 2.0 * 3600.0;
 
 void System_LaunchUrl(LaunchUrlType urlType, const char *url) {
-	ShellExecute(NULL, L"open", ConvertUTF8ToWString(url).c_str(), NULL, NULL, SW_SHOWNORMAL);
+	std::string u(url);
+	std::thread t = std::thread([u]() {
+		ShellExecute(NULL, L"open", ConvertUTF8ToWString(u).c_str(), NULL, NULL, SW_SHOWNORMAL);
+	});
+	// Detach is bad (given exit behavior), but in this case all the thread does is a ShellExecute to avoid freezing the caller while it runs, so it's safe.
+	t.detach();
 }
 
 void System_Vibrate(int length_ms) {