Fix compiler warnings seen on OpenBSD.

nmap.cc

@@ -2002,7 +2002,7 @@ int gather_logfile_resumption_state(char *fname, int *myargc, char ***myargv) {
     fatal("Unable to parse supposed log file %s.  Perhaps the Nmap execution had not finished at least one host?  In that case there is no use \"resuming\"", fname);
 
 
-  strcpy(nmap_arg_buffer, "nmap --append-output ");
+  strncpy(nmap_arg_buffer, "nmap --append-output ", sizeof(nmap_arg_buffer));
   if ((q-p) + 21 + 1 >= (int) sizeof(nmap_arg_buffer)) fatal("0verfl0w");
   memcpy(nmap_arg_buffer + 21, p, q-p);
   nmap_arg_buffer[21 + q-p] = '\0';

osscan2.cc

@@ -2702,7 +2702,7 @@ bool HostOsScan::get_tcpopt_string(struct tcp_hdr *tcp, int mss, char *result, i
         break; /* Window Scale option has 3 bytes */
       *p++ = 'W';
       q++;
-      sprintf(p, "%hX", *((u8*)q));
+      snprintf(p, length, "%hX", *((u8*)q));
       p += strlen(p); /* max movement of p is 2 (max WScale value is 0xFF) */
       q++;
       length -= 3;

output.cc

@@ -549,7 +549,7 @@ void printportoutput(Target * currenths, PortList * plist) {
       fatal("Unable to properly format host start time");
 
     log_write(LOG_PLAIN, "Scanned at %s for %lds\n",
-              tbufs, tm_sece - tm_secs);
+              tbufs, (long) (tm_sece - tm_secs));
   }
   log_write(LOG_MACHINE, "Host: %s (%s)", currenths->targetipstr(),
             currenths->HostName());