Request Etherboot encapsulated options.

Parameter request list is yet another option that ISC dhcpd ignores
unless it's in the main options block.

Fix logic error in parsing file and sname fields.

src/net/udp/dhcp.c

 	DHCP_VENDOR_CLASS_ID,
 	DHCP_STRING (  'E', 't', 'h', 'e', 'r', 'b', 'o', 'o', 't' ),
 	DHCP_PARAMETER_REQUEST_LIST,
-	DHCP_OPTION ( DHCP_SUBNET_MASK, DHCP_ROUTERS, DHCP_HOST_NAME ),
+	DHCP_OPTION ( DHCP_SUBNET_MASK, DHCP_ROUTERS, DHCP_HOST_NAME,
+		      DHCP_EB_ENCAP ),
 	DHCP_END
 };
 
 		return 0;
 	case DHCP_MESSAGE_TYPE:
 	case DHCP_REQUESTED_ADDRESS:
+	case DHCP_PARAMETER_REQUEST_LIST:
 		/* These options have to be within the main options
 		 * block.  This doesn't seem to be required by the
 		 * RFCs, but at least ISC dhcpd refuses to recognise
 	/* Merge in "file" and "sname" fields */
 	merge_dhcp_field ( options, dhcphdr->file, sizeof ( dhcphdr->file ),
 			   ( ( overloading & DHCP_OPTION_OVERLOAD_FILE ) ?
-			     DHCP_BOOTFILE_NAME : 0 ) );
+			     0 : DHCP_BOOTFILE_NAME ) );
 	merge_dhcp_field ( options, dhcphdr->sname, sizeof ( dhcphdr->sname ),
 			   ( ( overloading & DHCP_OPTION_OVERLOAD_SNAME ) ?
-			     DHCP_TFTP_SERVER_NAME : 0 ) );
+			     0 : DHCP_TFTP_SERVER_NAME ) );
 
 	/* Set magic options for "yiaddr" and "siaddr", if present */
 	if ( dhcphdr->yiaddr.s_addr ) {