make --daemon-id a coin-specific cfg file option

mmgen/cfg.py

@@ -292,6 +292,7 @@ class Config(Lockable):
 		'autosign',
 		'color',
 		'daemon_data_dir',
+		'daemon_id', # also coin-specific
 		'debug',
 		'fee_adjust',
 		'force_256_color',

mmgen/daemon.py

@@ -367,7 +367,11 @@ class CoinDaemon(Daemon):
 		daemon_ids = cls.get_daemon_ids(cfg, coin)
 		if not daemon_ids:
 			die(1, f'No configured daemons for coin {coin}!')
-		daemon_id = daemon_id or cfg.daemon_id or daemon_ids[0]
+		daemon_id = (
+			daemon_id
+			or getattr(cfg, f'{coin.lower()}_daemon_id', None)
+			or cfg.daemon_id
+			or daemon_ids[0])
 
 		if daemon_id not in daemon_ids:
 			die(1, f'{daemon_id!r}: invalid daemon_id - valid choices: {fmt_list(daemon_ids)}')

mmgen/data/mmgen.cfg

@@ -77,6 +77,10 @@
 # setups with unusually large Monero wallets:
 # macos_autosign_ramdisk_size 10
 
+# Specify the daemon ID.  This option also has coin-specific variants (see
+# below):
+# daemon_id bitcoin_core
+
 # Ignore coin daemon version. This option also has coin-specific variants
 # (see below):
 # ignore_daemon_version false

mmgen/opts.py

@@ -337,6 +337,7 @@ class UserOpts(Opts):
 			rr   For descriptions, refer to the non-prefixed versions of these options above
 			rr   Prefixed options override their non-prefixed counterparts
 			rr   OPTION                            SUPPORTED PREFIXES
+			Rr --PREFIX-daemon-id                btc ltc bch eth etc
 			rr --PREFIX-ignore-daemon-version    btc ltc bch eth etc xmr
 			br --PREFIX-tw-name                  btc ltc bch
 			Rr --PREFIX-rpc-host                 btc ltc bch eth etc

mmgen/proto/btc/params.py

@@ -55,6 +55,7 @@ class mainnet(CoinProtocol.Secp256k1): # chainparams.cpp
 	max_op_return_data_len = 80
 
 	coin_cfg_opts = (
+		'daemon_id',
 		'ignore_daemon_version',
 		'rpc_host',
 		'rpc_port',

mmgen/proto/eth/params.py

@@ -55,6 +55,7 @@ class mainnet(CoinProtocol.DummyWIF, CoinProtocol.Secp256k1):
 	}
 
 	coin_cfg_opts = (
+		'daemon_id',
 		'ignore_daemon_version',
 		'rpc_host',
 		'rpc_port',

mmgen/protocol.py

@@ -212,6 +212,7 @@ class CoinProtocol(MMGenObject):
 		rpc_user              = ''
 		rpc_password          = ''
 		tw_name               = ''
+		daemon_id             = ''
 
 		@classmethod
 		def get_opt_clsval(cls, cfg, opt):