message: Fix wrong welcome screen layout with macOS tab bar
  If the tab bar is enabled, initial Poedit screen would show buttons
  with mangled text due to incorrect sizing on macOS 10.12+.
diff: @@ -56,8 +56,10 @@ class ActionButton : public wxWindow
  {
  public:
  ActionButton(wxWindow *parent, wxWindowID winid, const wxString& label, const wxString& note)
  - : wxWindow(parent, wxID_ANY, wxDefaultPosition, wxSize(500, 65))
  + : wxWindow(parent, wxID_ANY)
  {
  + SetMinSize(wxSize(500, 65));
  +
  m_button = new wxButton(this, winid, "");
  auto sizer = new wxBoxSizer(wxHORIZONTAL);
  sizer->Add(m_button, wxSizerFlags(1).Expand());
  