Fixes for windows (#45)

* init Net system on Windows

* propagate DNS error

* Add zlib 1.2.11 sources

* link zlib statically for windows

* remove not implemented function declaration

* fix connect on Windows

ixwebsocket/IXDNSLookup.cpp

@@ -27,7 +27,7 @@ namespace ix
         _done(false),
         _id(_nextId++)
     {
-
+        initNetSystem();
     }
 
     DNSLookup::~DNSLookup()
@@ -137,6 +137,11 @@ namespace ix
             return nullptr;
         }
 
+        if (!_errMsg.empty())
+        {
+            errMsg = _errMsg;
+        }
+
         std::unique_lock<std::mutex> rlock(_resMutex);
         return _res;
     }

ixwebsocket/IXNetSystem.cpp

@@ -0,0 +1,39 @@
+/*
+ *  IXNetSystem.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone. All rights reserved.
+ */
+
+#include "IXNetSystem.h"
+
+namespace ix
+{
+    bool initNetSystem()
+    {
+#ifdef _WIN32
+        WORD wVersionRequested;
+        WSADATA wsaData;
+        int err;
+
+        /* Use the MAKEWORD(lowbyte, highbyte) macro declared in Windef.h */
+        wVersionRequested = MAKEWORD(2, 2);
+
+        err = WSAStartup(wVersionRequested, &wsaData);
+
+        return err == 0;
+#else
+        return true;
+#endif
+    }
+
+    bool uninitNetSystem()
+    {
+#ifdef _WIN32
+        int err = WSACleanup();
+
+        return err == 0;
+#else
+        return true;
+#endif
+    }
+}

ixwebsocket/IXNetSystem.h

@@ -23,3 +23,9 @@
 # include <sys/time.h>
 # include <unistd.h>
 #endif
+
+namespace ix
+{
+    bool initNetSystem();
+    bool uninitNetSystem();
+}

ixwebsocket/IXSocketConnect.cpp

@@ -57,10 +57,10 @@ namespace ix
         SocketConnect::configure(fd);
 
         if (::connect(fd, address->ai_addr, address->ai_addrlen) == -1
-            && errno != EINPROGRESS)
+            && errno != EINPROGRESS && errno != 0)
         {
-            closeSocket(fd);
             errMsg = strerror(errno);
+            closeSocket(fd);
             return -1;
         }