Allow producing block with execution payload

beacon_node/src/cli.rs

@@ -380,6 +380,17 @@ pub fn cli_app<'a, 'b>() -> App<'a, 'b> {
                        Be extremely careful with the use of this flag.")
                 .takes_value(true)
         )
+        .arg(
+            Arg::with_name("fee-recipient")
+                .long("fee-recipient")
+                .help("Once the merge has happened, this address will receive transaction fees \
+                       collected from any blocks produced by this node. Defaults to a junk \
+                       address whilst the merge is in development stages. THE DEFAULT VALUE \
+                       WILL BE REMOVED BEFORE THE MERGE ENTERS PRODUCTION")
+                // TODO: remove this default value. It's just there to make life easy during merge
+                // testnets.
+                .default_value("0x000000000000000000000000000000000000000000000001"),
+        )
 
         /*
          * Database purging and compaction.

beacon_node/src/config.rs

@@ -237,6 +237,8 @@ pub fn get_config<E: EthSpec>(
         client_config.terminal_total_difficulty_override = Some(terminal_total_difficulty);
     }
 
+    client_config.fee_recipient = clap_utils::parse_optional(cli_args, "fee-recipient")?;
+
     if let Some(freezer_dir) = cli_args.value_of("freezer-dir") {
         client_config.freezer_db_path = Some(PathBuf::from(freezer_dir));
     }