remove the rest of gcc compiler warnings

.vscode/settings.json

@@ -64,6 +64,7 @@
     "map": "cpp",
     "vector": "cpp",
     "new": "cpp",
-    "shared_mutex": "cpp"
+    "shared_mutex": "cpp",
+    "complex": "cpp"
   }
 }

llarp/dns.cpp

@@ -127,12 +127,13 @@ extern "C"
   void
   code_domain(char *&buffer, const std::string &domain) throw()
   {
-    int start(0), end;  // indexes
+    std::string::size_type start(0);
+    std::string::size_type end;  // indexes
     // llarp::LogInfo("domain [", domain, "]");
     while((end = domain.find('.', start)) != std::string::npos)
     {
       *buffer++ = end - start;  // label length octet
-      for(int i = start; i < end; i++)
+      for(std::string::size_type i = start; i < end; i++)
       {
         *buffer++ = domain[i];  // label octets
         // llarp::LogInfo("Writing ", domain[i], " at ", i);