Fix warnings

Warnings came up using MinGW 4.4:
* botan.cpp: integer constant is too large for 'long' type
* dnssd_clientlib.c, dnssd_clientstub.c: ignoring #pragma warning
* hostutils.cpp: comparison between signed and unsigned integer expressions
* qmakebuildins.cpp: 'QString windowsErrorCode()' defined but not used

Change-Id: I80827f7f740ff380f13cef96d6b43baaa7e179cb
Reviewed-by: Christian Kandeler <christian.kandeler@nokia.com>
Reviewed-by: hjk <qthjk@ovi.com>

src/shared/proparser/qmakebuiltins.cpp

@@ -184,7 +184,7 @@ static bool isTrue(const ProString &_str, QString &tmp)
     return !str.compare(statics.strtrue, Qt::CaseInsensitive) || str.toInt();
 }
 
-#ifdef Q_OS_WIN
+#if defined(Q_OS_WIN) && defined(PROEVALUATOR_FULL)
 static QString windowsErrorCode()
 {
     wchar_t *string = 0;