Fix filesystem icons on windows.

We now use filesystem icons on all platforms so
we might as well enable proper support on windows again.

src/plugins/coreplugin/fileiconprovider.cpp

@@ -74,7 +74,7 @@ QIcon FileIconProvider::icon(const QFileInfo &fileInfo)
 
         // Disabled since for now we'll make sure that all icons fit with our
         // own custom icons by returning an empty one if we don't know it.
-#if 0
+#ifdef Q_OS_WIN
         // This is incorrect if the OS does not always return the same icon for the
         // same suffix (Mac OS X), but should speed up the retrieval a lot ...
         icon = m_systemIconProvider.icon(fileInfo);
@@ -127,7 +127,7 @@ void FileIconProvider::registerIconOverlayForSuffix(const QIcon &icon, const QSt
 QIcon FileIconProvider::iconForSuffix(const QString &suffix) const
 {
     QIcon icon;
-
+#ifndef Q_OS_WIN // On windows we use the file system icons
     if (suffix.isEmpty())
         return icon;
 
@@ -138,7 +138,7 @@ QIcon FileIconProvider::iconForSuffix(const QString &suffix) const
             break;
         }
     }
-
+#endif
     return icon;
 }