Filter duplicate server history entries

A server can be specified in many different ways, so it is easy to get
multiple entries in the history for the same thing.

Get rid of these by parsing each entry and comparing with existing
entries.

vncviewer/ServerDialog.cxx

@@ -37,6 +37,7 @@
 
 #include <os/os.h>
 #include <rfb/Exception.h>
+#include <rfb/Hostname.h>
 #include <rfb/LogWriter.h>
 #include <rfb/util.h>
 
@@ -306,14 +307,42 @@ void ServerDialog::handleConnect(Fl_Widget* /*widget*/, void *data)
 }
 
 
+static bool same_server(const string& a, const string& b)
+{
+  string hostA, hostB;
+  int portA, portB;
+
+#ifndef WIN32
+  if ((a.find("/") != string::npos) || (b.find("/") != string::npos))
+    return a == b;
+#endif
+
+  try {
+    getHostAndPort(a.c_str(), &hostA, &portA);
+    getHostAndPort(b.c_str(), &hostB, &portB);
+  } catch (Exception& e) {
+    return false;
+  }
+
+  if (hostA != hostB)
+    return false;
+
+  if (portA != portB)
+    return false;
+
+  return true;
+}
+
+
 void ServerDialog::loadServerHistory()
 {
+  list<string> rawHistory;
+
   serverHistory.clear();
 
 #ifdef _WIN32
-  serverHistory = loadHistoryFromRegKey();
-  return;
-#endif
+  rawHistory = loadHistoryFromRegKey();
+#else
 
   const char* stateDir = os::getvncstatedir();
   if (stateDir == nullptr)
@@ -369,10 +398,19 @@ void ServerDialog::loadServerHistory()
     if (len == 0)
       continue;
 
-    serverHistory.push_back(line);
+    rawHistory.push_back(line);
   }
 
   fclose(f);
+#endif
+
+  // Filter out duplicates, even if they have different formats
+  for (const string& entry : rawHistory) {
+    if (std::find_if(serverHistory.begin(), serverHistory.end(),
+                     [&entry](const string& s) { return same_server(s, entry); }) != serverHistory.end())
+      continue;
+    serverHistory.push_back(entry);
+  }
 }
 
 void ServerDialog::saveServerHistory()