Also add wxNativeFontInfo::SetStrikethrough() stub for wxGTK2.

This should have been done in r70563 which added the stub to wxGTK1 part only.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@70566 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/unix/fontutil.cpp

@@ -272,6 +272,11 @@ void wxNativeFontInfo::SetUnderlined(bool WXUNUSED(underlined))
     wxFAIL_MSG( "not implemented" );
 }
 
+void wxNativeFontInfo::SetStrikethrough(bool WXUNUSED(strikethrough))
+{
+    wxFAIL_MSG( "not implemented" );
+}
+
 bool wxNativeFontInfo::SetFaceName(const wxString& facename)
 {
     pango_font_description_set_family(description, wxPANGO_CONV(facename));