This patch switches the MINIX3 ethernet driver stack from a port-based

model to an instance-based model. Each ethernet driver instance is now
responsible for exactly one network interface card. The port field in
/etc/inet.conf now acts as an instance field instead.

This patch also updates the data link protocol. This update:
- eliminates the concept of ports entirely;
- eliminates DL_GETNAME entirely;
- standardizes on using m_source for IPC and DL_ENDPT for safecopies;
- removes error codes from TASK/STAT replies, as they were unused;
- removes a number of other old or unused fields;
- names and renames a few other fields.

All ethernet drivers have been changed to:
- conform to the new protocol, and exactly that;
- take on an instance number based on a given "instance" argument;
- skip that number of PCI devices in probe iterations;
- use config tables and environment variables based on that number;
- no longer be limited to a predefined maximum of cards in any way;
- get rid of any leftover non-safecopy support and other ancient junk;
- have a correct banner protocol figure, or none at all.

Other changes:
* Inet.conf is now taken to be line-based, and supports #-comments.
  No existing installations are expected to be affected by this.
* A new, select-based asynchio library replaces the old one.
  Kindly contributed by Kees J. Bot.
* Inet now supports use of select() on IP devices.
  Combined, the last two changes together speed up dhcpd
  considerably in the presence of multiple interfaces.
* A small bug has been fixed in nonamed.

lib/libnetdriver/netdriver.c

@@ -64,7 +64,7 @@ int *status_ptr;
 		if(m_ptr->m_type == DL_CONF) {
 			conf_expected = FALSE;
 		}
-		else if(m_ptr->m_type != DL_GETNAME) {
+		else {
 			continue;
 		}
 	}