net/tcpview: Permanently fix LLVM15 errors

Fix int-conversion errors flagged by LLVM15.

detail-domain.c:573:13: error: incompatible pointer to integer conversion
returning 'void *' from a function with result type 'int' [-Wint-conversion]
            return NULL;
                   ^~~~
/usr/include/sys/_null.h:34:14: note: expanded from macro 'NULL'
                ^~~~~~~~~~~

net/tcpview/Makefile

@@ -13,8 +13,6 @@ USES=		bison motif tar:Z
 MAKE_ARGS=	PREFIX=${STAGEDIR}${PREFIX}
 MAKE_JOBS_UNSAFE=	yes
 
-CFLAGS=		-Wno-int-conversion
-
 post-patch:
 .for f in nametoaddr.c addrtoname.c print-nfs.c detail-tcp.c tv_addrtoname.c
 	@${REINPLACE_CMD} -e 's/NTOHL/ntohl/ ; s/NTOHS/ntohs/' ${WRKSRC}/${f}

net/tcpview/files/patch-detail-domain.c

@@ -1,6 +1,14 @@
---- detail-domain.c.orig	1993-04-22 20:39:51 UTC
+--- detail-domain.c.orig	1993-04-22 13:39:51.000000000 -0700
-+++ detail-domain.c
++++ detail-domain.c	2023-02-14 21:16:01.401668000 -0800
-@@ -199,6 +199,7 @@ p_type(type)
+@@ -103,6 +103,7 @@
+ 
+ #define FAIL 1
+ #define SUCCEED 0
++#define IGNORE 0
+ #define MIN(a,b) (((a)<(b))?(a):(b))
+ 
+ 
+@@ -199,6 +200,7 @@
        case T_ANY:		/* matches any type */
  	strcpy(type_buf, "ANY");
  	break;
@@ -8,7 +16,7 @@
        case T_UINFO:
  	strcpy(type_buf, "UINFO");
  	break;
-@@ -211,6 +212,7 @@ p_type(type)
+@@ -211,6 +213,7 @@
        case T_UNSPEC:
  	strcpy(type_buf, "UNSPEC");
          break;
@@ -16,7 +24,120 @@
        default:
  	sprintf(type_buf, "%d", type);
          break;
-@@ -633,6 +635,7 @@ p_ans(msg, eom)
+@@ -444,7 +447,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    Canonical name = %s\n", str);
+ 	MARK_WINDOW();
+@@ -455,7 +458,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    MB domain name = %s\n", str);
+ 	MARK_WINDOW();
+@@ -466,7 +469,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    MD domain name = %s (obsolete)\n", str);
+ 	MARK_WINDOW();
+@@ -477,7 +480,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    MF domain name = %s (obsolete)\n", str);
+ 	MARK_WINDOW();
+@@ -488,7 +491,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    Mail group member = %s\n", str);
+ 	MARK_WINDOW();
+@@ -499,7 +502,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    Mail rename domain name = %s\n", str);
+ 	MARK_WINDOW();
+@@ -512,7 +515,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    Mail exchangeer = %s, preference %u\n", str, pref);
+ 	MARK_WINDOW();
+@@ -523,7 +526,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    Authoritative name server = %s\n", str);
+ 	MARK_WINDOW();
+@@ -534,7 +537,7 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+         printf("    Domain name pointer = %s\n", str);
+ 	MARK_WINDOW();
+@@ -568,7 +571,7 @@
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+ 	    MARK_SAVED_WIN(saveind, -1, -1);
+-	    return NULL;
++	    return IGNORE;
+ 	}
+ 	printf("      Origin: %s\n", str);
+ 	MARK_WINDOW();
+@@ -578,7 +581,7 @@
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+ 	    MARK_SAVED_WIN(saveind, -1, -1);
+-	    return NULL;
++	    return IGNORE;
+ 	}
+ 	printf("      Mail Addr: %s\n", str);
+ 	MARK_WINDOW();
+@@ -621,18 +624,19 @@
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
+ 	printf("    MINFO: requests = %s", str);
+ 	str = p_cdname(msg, eom);
+         if (str == NULL) {
+ 	    printf(" ** Data truncated **\n");
+ 	    MARK_WINDOW_NONE();
+-	    return NULL;
++	    return IGNORE;
+ 	}
  	printf("; errors = %s\n", str);
  	MARK_WINDOW();
  
@@ -24,7 +145,7 @@
        case T_UINFO:
          printf("    UINFO: ");
          printf("%s\n", cp);
-@@ -654,6 +657,12 @@ p_ans(msg, eom)
+@@ -654,6 +658,12 @@
  	MARK_WINDOW();
          break;
  
@@ -37,7 +158,7 @@
        case T_WKS:
          if (rdlength < (int)(sizeof(u_long) + 1))
              break;
-@@ -730,11 +739,6 @@ p_ans(msg, eom)
+@@ -730,11 +740,6 @@
  	break;