File/dir dialog styles and other changes (patch 1488371):

- check invalid combinations of styles in wxFileDialogBase::Create()
- use wxFD_XXX naming convention for wxFileDialog styles
- replaces wxDD_NEW_DIR_BUTTON with wxDD_DIR_MUST_EXIST
- removes #ifdef __WXGTK24__ / #endif blocks from wxGTK code
- removes wxFileDialogBase::Get/SetStyle and wxFileDialogBase::m_fileName
- renames wxDirDialogGTK to wxDirDialog


git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@39402 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/html/helpwnd.cpp

@@ -1533,7 +1533,7 @@ void wxHtmlHelpWindow::OnToolbar(wxCommandEvent& event)
                                             wxEmptyString,
                                             wxEmptyString,
                                             filemask,
-                                            wxOPEN | wxFILE_MUST_EXIST,
+                                            wxFD_OPEN | wxFD_FILE_MUST_EXIST,
                                             this);
                 if (!s.empty())
                 {