Make DNS optional

Makefile

@@ -1,9 +1,9 @@
 dnsseed: dns.o bitcoin.o netbase.o protocol.o db.o main.o
-	g++ -pthread -lssl -o dnsseed dns.o bitcoin.o netbase.o protocol.o db.o main.o
+	g++ -pthread -lcrypto -o dnsseed dns.o bitcoin.o netbase.o protocol.o db.o main.o
 	strip -s dnsseed
 
 dnsseed.dbg: dns.o bitcoin.o netbase.o protocol.o db.o main.o
-	g++ -pthread -lssl -o dnsseed.dbg dns.o bitcoin.o netbase.o protocol.o db.o main.o
+	g++ -pthread -lcrypto -o dnsseed.dbg dns.o bitcoin.o netbase.o protocol.o db.o main.o
 
 %.o: %.cpp bitcoin.h netbase.h protocol.h db.h serialize.h uint256.h util.h
 	g++ -pthread -O3 -ggdb3 -march=nocona -Wno-invalid-offsetof -c -o $@ $<

main.cpp

@@ -220,11 +220,12 @@ int main(int argc, char **argv) {
   setbuf(stdout, NULL);
   CDnsSeedOpts opts;
   opts.ParseCommandLine(argc, argv);
+  bool fDNS = true;
   if (!opts.ns) {
-    fprintf(stderr, "No nameserver set. Please use -n.\n");
-    exit(1);
+    printf("No nameserver set. Not starting DNS server.\n");
+    fDNS = false;
   }
-  if (!opts.host) {
+  if (fDNS && !opts.host) {
     fprintf(stderr, "No hostname set. Please use -h.\n");
     exit(1);
   }
@@ -247,11 +248,13 @@ int main(int argc, char **argv) {
   }
   printf("done\n");
   pthread_create(&threadDump, NULL, ThreadDumper, NULL);
+  if (fDNS) {
     printf("Starting DNS server for %s on %s (port %i)...", opts.host, opts.ns, opts.nPort);
     pthread_create(&threadDns, NULL, ThreadDNS, &opts);
     printf("done\n");
+  }
   pthread_create(&threadStats, NULL, ThreadStats, NULL);
   void* res;
-  pthread_join(threadDns, &res);
+  pthread_join(threadDump, &res);
   return 0;
 }