Fix build with libpcap 1.10 and later, which has its own pcap_init function.
--- trafshow.c.orig	2021-05-11 16:50:08.000000000 +0930
+++ trafshow.c	2021-05-11 16:52:05.000000000 +0930
@@ -58,7 +58,7 @@
 static void vers();
 static void usage();
 static pcap_if_t *pcap_matchdev(pcap_if_t *dp, const char *name);
-static int pcap_init(PCAP_HANDLER **ph_list, pcap_if_t *dp);
+static int pcap_doinit(PCAP_HANDLER **ph_list, pcap_if_t *dp);
 static void *pcap_feed(void *arg); /* PCAP_HANDLER *ph */
 #ifdef	HAVE_PCAP_GET_SELECTABLE_FD
 static void *pcap_feed2(void *arg); /* PCAP_HANDLER *ph */
@@ -172,7 +172,7 @@
 	}
 
 	/* initialize list of pcap handlers */
-	if ((op = pcap_init(&ph_list, dev_list)) < 1) {
+	if ((op = pcap_doinit(&ph_list, dev_list)) < 1) {
 		fprintf(stderr, "No packet capture device available (no permission?)\n");
 		exit(1);
 	}
@@ -298,7 +298,7 @@
 }
 
 static int
-pcap_init(ph_list, dp)
+pcap_doinit(ph_list, dp)
 	PCAP_HANDLER **ph_list;
 	pcap_if_t *dp;
 {