added decoration for about box on non-MacOS

git-svn-id: http://svn.osgeo.org/qgis/trunk/qgis@10371 c8812cc2-4d05-0410-92ff-de0c093fc19c

src/app/qgsabout.cpp

@@ -31,9 +31,13 @@
 #include "qgslogger.h"
 std::map<QString, QPixmap> mugs;
 */
-
+#ifdef Q_OS_MACX
 QgsAbout::QgsAbout()
     : QDialog( NULL, Qt::WindowSystemMenuHint )  // Modeless dialog with close button only
+#else
+QgsAbout::QgsAbout()
+    : QDialog( NULL )  // Normal dialog in non Mac-OS
+#endif
 {
   setupUi( this );
   init();