Add client/server fromEnv() without temporary Config on caller stack

example/rpc_server.cpp

@@ -71,8 +71,7 @@ int main(int argc, char* argv[])
 
     // Build server which will serve this PV
     // Configure using process environment.
-    server::Server serv = server::Config::fromEnv()
-            .build()
+    server::Server serv = server::Server::fromEnv()
             .addPV(argv[1], pv);
 
     // (optional) Print the configuration this server is using