net/SocketDescriptor: add AcceptNonBlock() overload without address

src/net/SocketDescriptor.cxx

@@ -69,6 +69,20 @@ SocketDescriptor::Accept()
 }
 
 SocketDescriptor
+SocketDescriptor::AcceptNonBlock() const
+{
+#ifdef HAVE_ACCEPT4
+	int connection_fd = ::accept4(Get(), nullptr, nullptr,
+				      SOCK_CLOEXEC|SOCK_NONBLOCK);
+#else
+	int connection_fd = ::accept(Get(), nullptr, nullptr);
+	if (connection_fd >= 0)
+		SocketDescriptor(connection_fd).SetNonBlocking();
+#endif
+	return SocketDescriptor(connection_fd);
+}
+
+SocketDescriptor
 SocketDescriptor::AcceptNonBlock(StaticSocketAddress &address) const
 {
 	address.SetMaxSize();

src/net/SocketDescriptor.hxx

@@ -173,6 +173,7 @@ public:
 	bool Listen(int backlog);
 
 	SocketDescriptor Accept();
+	SocketDescriptor AcceptNonBlock() const;
 	SocketDescriptor AcceptNonBlock(StaticSocketAddress &address) const;
 
 	bool Connect(SocketAddress address);

src/net/UniqueSocketDescriptor.hxx

@@ -79,6 +79,13 @@ public:
 	/**
 	 * @return an "undefined" instance on error
 	 */
+	UniqueSocketDescriptor AcceptNonBlock() const {
+		return UniqueSocketDescriptor(SocketDescriptor::AcceptNonBlock());
+	}
+
+	/**
+	 * @return an "undefined" instance on error
+	 */
 	UniqueSocketDescriptor AcceptNonBlock(StaticSocketAddress &address) const {
 		return UniqueSocketDescriptor(SocketDescriptor::AcceptNonBlock(address));
 	}