bug#1665: face-foreground on Mac OS 10.4.11

[Alex Schröder]

face-foreground doesn't return the correct foreground color if it is
inherited. In the following example test has a purple foreground,
test2 inherits from test, and both have a purple foreground when I
look at them using list-faces-display. (face-foreground "test2")
returns nil, however.

(progn
  (make-face 'test)
  (set-face-foreground 'test "purple")
  (assert (string= (face-foreground 'test)
                   "purple"))
  (defface test2 '((t (:inherit test))) "Test")
  (assert (string= (face-foreground 'test2)
                   "purple")))

In GNU Emacs 23.0.60.1 (i386-apple-darwin8.11.1, NS apple-appkit-824.48)
 of 2008-12-21 on Pyrobombus.local
Windowing system distributor `Apple', version
97.112.112.108.101.45.97.112.112.107.105.116.45.56.50.52.46.52.56
configured using `configure  '--with-ns''