added missing conditional compilation test for wxUSE_PROPSHEET

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@11131 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

include/wx/propform.h

@@ -16,6 +16,8 @@
 #pragma interface "propform.h"
 #endif
 
+#if wxUSE_PROPSHEET
+
 #include "wx/prop.h"
 
 ////
@@ -324,5 +326,8 @@ private:
     DECLARE_CLASS(wxPropertyFormFrame)
 };
 
+#endif
+  // wxUSE_PROPSHEET
+
 #endif
   // _WX_PROPFORM_H_