[PATCH] use native file dialog on windows (fix major bug 3907)

[Abdelrazak Younes]

Hello,

Even though I like our file dialog, I think we have no choice but using 
native file dialog on Windows in order to fix bug 3907 (File -> Open 
dialog needs many seconds before it opens).

OK?

Abdel.
Index: FileDialog.cpp
===================================================================
--- FileDialog.cpp      (revision 18939)
+++ FileDialog.cpp      (working copy)
@@ -31,7 +31,7 @@
  *
  * Therefore there is a tradeoff in enabling or disabling this (JMarc)
  */
-#ifdef Q_WS_MACX
+#ifdef Q_WS_MACX || Q_WS_WIN
 #define USE_NATIVE_FILEDIALOG 1
 #endif