Function: display-supports-face-attributes-p

Return non-nil if all the face attributes in ATTRIBUTES are supported.
The optional argument DISPLAY can be a display name, a frame, or
nil (meaning the selected frame's display).

The definition of `supported' is somewhat heuristic, but basically means
that a face containing all the attributes in ATTRIBUTES, when merged
with the default face for display, can be represented in a way that's

(1) different in appearance than the default face, and
(2) `close in spirit' to what the attributes specify, if not exact.

Point (2) implies that a `:weight black' attribute will be satisfied by
any display that can display bold, and a `:foreground "yellow"' as long
as it can display a yellowish color, but `:slant italic' will _not_ be
satisfied by the tty display code's automatic substitution of a `dim' face for italic. (fn ATTRIBUTES &optional DISPLAY)