str which is marked up with the Pango text markup language, setting the
label's text and attribute list based on the parse results. If the str is
external data, you may need to escape it with gMarkupEscapeText() or
gMarkupPrintfEscaped():
## RGtk2 has no support for GMarkup
gtkLabelSetMarkup(object, str)objectGtkLabelstr