opdb: add option for setting default GDB port.

mspdebug.man

@@ -258,7 +258,8 @@ repeated without padding as many times as necessary without exceeding the
 bounds of the specified region.
 .IP "\fBgdb\fR [\fIport\fR]"
 Start a GDB remote stub, optionally specifying a TCP port to listen on.
-If no port is given, the default port is 2000.
+If no port is given, the default port is controlled by the option
+\fBgdb_default_port\fR.
 
 MSPDebug will wait for a connection on this port, and then act as a
 GDB remote stub until GDB disconnects.
@@ -715,6 +716,9 @@ BSL memory. If in doubt, do not enable this.
 If set, some drivers will allow erase/program access to the info A
 segment. If in doubt, do not enable this. Currently, the tilib and uif
 drivers are affected by this option.
+.IP "\fBgdb_default_port\fR (numeric)"
+This option controls the default TCP port for the GDB server, if no
+argument is given to the "\fBgdb\fR" command.
 .IP "\fBgdb_loop\fR (boolean)"
 Automatically restart the GDB server after disconnection. If this
 option is set, then the GDB server keeps running until an error occurs,

ui/gdb.c

@@ -536,7 +536,7 @@ static int gdb_server(int port)
 int cmd_gdb(char **arg)
 {
 	char *port_text = get_arg(arg);
-	address_t port = 2000;
+	address_t port = opdb_get_numeric("gdb_default_port");
 
 	if (port_text && expr_eval(port_text, &port) < 0) {
 		printc_err("gdb: can't parse port: %s\n", port_text);

util/opdb.c

@@ -94,6 +94,15 @@ static const struct opdb_key keys[] = {
 		.help =
 "If set, some drivers will allow erase/program access to flash\n"
 "BSL memory. If in doubt, do not enable this.\n"
+	},
+	{
+		.name = "gdb_default_port",
+		.type = OPDB_TYPE_NUMERIC,
+		.help =
+"Default TCP port for GDB server, if no argument is given.\n",
+		.defval = {
+			.numeric = 2000
+		}
 	}
 };