fix qextserial in mingw?

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@14333 c8812cc2-4d05-0410-92ff-de0c093fc19c

Author: jef

src/core/gps/qextserialport/qextserialenumerator.h

@@ -7,12 +7,16 @@
 #ifndef _QEXTSERIALENUMERATOR_H_
 #define _QEXTSERIALENUMERATOR_H_
 
-
 #include <QString>
 #include <QList>
 #include <QObject>
 
 #ifdef Q_OS_WIN
+    #ifdef __MINGW32__
+        #define _WIN32_WINNT 0x0500
+        #define _WIN32_WINDOWS 0x0500
+        #define WINVER 0x0500 
+    #endif
     #include <windows.h>
     #include <setupapi.h>
     #include <dbt.h>