nghttpx: Disallow copying Config

src/shrpx.cc

@@ -1272,8 +1272,6 @@ constexpr auto DEFAULT_ACCESSLOG_FORMAT = StringRef::from_lit(
 
 namespace {
 void fill_default_config(Config *config) {
-  *config = {};
-
   config->num_worker = 1;
   config->conf_path = "/etc/nghttpx/nghttpx.conf";
   config->pid = getpid();

src/shrpx_config.h

@@ -706,8 +706,14 @@ struct APIConfig {
 };
 
 struct Config {
+  Config() = default;
   ~Config();
 
+  Config(Config &&) = delete;
+  Config(const Config &&) = delete;
+  Config &operator=(Config &&) = delete;
+  Config &operator=(const Config &&) = delete;
+
   HttpProxy downstream_http_proxy;
   HttpConfig http;
   Http2Config http2;