Define ETHERTYPE_{SLOW,LLDP} and accept them in pcap_nametoeproto()

The nomenclature for SLOW follows common practice; Linux uses
	#define ETH_P_SLOW	0x8809		/* Slow Protocol. See 802.3ad 43B */
	#define ETH_P_LLDP	0x88CC		/* Link Layer Discovery Protocol */

SLOW carries IEEE 802.3 LACP, both defined in annex 57A of 802.3-2018:
  https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=8457469
and LLDP is defined in sexion 79 of the same.

Author: nabijaczleweli

ethertype.h

@@ -100,6 +100,9 @@
 #ifndef ETHERTYPE_IPV6
 #define ETHERTYPE_IPV6		0x86dd
 #endif
+#ifndef ETHERTYPE_SLOW
+#define ETHERTYPE_SLOW		0x8809	/* Organization-specific slow protocol */
+#endif
 #ifndef ETHERTYPE_MPLS
 #define ETHERTYPE_MPLS		0x8847
 #endif
@@ -115,6 +118,9 @@
 #ifndef ETHERTYPE_8021AD
 #define ETHERTYPE_8021AD	0x88a8
 #endif
+#ifndef ETHERTYPE_LLDP
+#define ETHERTYPE_LLDP		0x88cc	/* Layer Discovery Protocol */
+#endif
 #ifndef	ETHERTYPE_LOOPBACK
 #define ETHERTYPE_LOOPBACK	0x9000
 #endif

nametoaddr.c

@@ -571,11 +571,13 @@ PCAP_API_DEF struct eproto eproto_db[] = {
 	{ "ip", ETHERTYPE_IP },
 	{ "ip6", ETHERTYPE_IPV6 },
 	{ "lat", ETHERTYPE_LAT },
+	{ "lldp", ETHERTYPE_LLDP },
 	{ "loopback", ETHERTYPE_LOOPBACK },
 	{ "mopdl", ETHERTYPE_MOPDL },
 	{ "moprc", ETHERTYPE_MOPRC },
 	{ "rarp", ETHERTYPE_REVARP },
 	{ "sca", ETHERTYPE_SCA },
+	{ "slow", ETHERTYPE_SLOW },
 	{ (char *)0, 0 }
 };