Sets the relief style of the edges of the given #GtkButton widget.
Two styles exist, %GTK_RELIEF_NORMAL and %GTK_RELIEF_NONE.
The default style is, as one can guess, %GTK_RELIEF_NORMAL.
The deprecated value %GTK_RELIEF_HALF behaves the same as
%GTK_RELIEF_NORMAL.
Sets the relief style of the edges of the given #GtkButton widget. Two styles exist, %GTK_RELIEF_NORMAL and %GTK_RELIEF_NONE. The default style is, as one can guess, %GTK_RELIEF_NORMAL. The deprecated value %GTK_RELIEF_HALF behaves the same as %GTK_RELIEF_NORMAL.