Reintroduce MSVC workaround

...originally introduced with 02abccf9 but
erroneously purged with 9c2f7056.

svl/inc/svl/style.hxx

@@ -285,6 +285,7 @@ public:
     virtual sal_Bool        SetParent( const UniString& );
 
 protected:
+    SfxStyleSheet(); // do not use! needed by MSVC
     virtual             ~SfxStyleSheet();
 };
 

svl/source/items/style.cxx

@@ -884,6 +884,10 @@ SfxStyleSheet::SfxStyleSheet(const SfxStyleSheet& rStyle) :
     SfxBroadcaster( rStyle )
 {}
 
+SfxStyleSheet::SfxStyleSheet()
+{
+}
+
 SfxStyleSheet::~SfxStyleSheet()
 {
     Broadcast( SfxStyleSheetHint( SFX_STYLESHEET_INDESTRUCTION, *this ) );