Partially revert last Gnus merge.

The add-face function has been added gnus-compat.el, but is not in
Emacs; this leaves Gnus in an unusable state.

* lisp/gnus/gnus-salt.el (gnus-tree-highlight-node):
* lisp/gnus/gnus-sum.el (gnus-summary-highlight-line):
* lisp/gnus/gnus-group.el (gnus-group-highlight-line): Revert use of add-face.

* lisp/gnus/gnus-util.el (gnus-put-text-property-excluding-characters-with-faces): Restore.

lisp/gnus/ChangeLog

+2012-09-07  Chong Yidong  <cyd@gnu.org>
+
+	* gnus-util.el
+	(gnus-put-text-property-excluding-characters-with-faces): Restore.
+
+	* gnus-salt.el (gnus-tree-highlight-node):
+	* gnus-sum.el (gnus-summary-highlight-line):
+	* gnus-group.el (gnus-group-highlight-line): Revert use of add-face.
+
 2012-09-06  Lars Ingebrigtsen  <larsi@gnus.org>
 	* gnus-util.el: Fix compilation error on XEmacs 21.4.

lisp/gnus/gnus-group.el

@@ -1669,7 +1669,9 @@ and ends at END."
                       gnus-group-highlight))))
     (unless (eq face (get-text-property beg 'face))
       (let ((inhibit-read-only t))
-        (add-face beg end (if (boundp face) (symbol-value face) face)))
+        (gnus-put-text-property-excluding-characters-with-faces
+         beg end 'face
+         (if (boundp face) (symbol-value face) face)))
       (gnus-extent-start-open beg))))
 
 (defun gnus-group-get-icon (group)

lisp/gnus/gnus-salt.el

@@ -660,7 +660,9 @@ Two predefined functions are available:
 		    (not (eval (caar list))))
 	  (setq list (cdr list)))))
     (unless (eq (setq face (cdar list)) (get-text-property beg 'face))
-      (add-face beg end (if (boundp face) (symbol-value face) face)))))
+      (gnus-put-text-property-excluding-characters-with-faces
+       beg end 'face
+       (if (boundp face) (symbol-value face) face)))))
 
 (defun gnus-tree-indent (level)
   (insert (make-string (1- (* (1+ gnus-tree-node-length) level)) ? )))

lisp/gnus/gnus-sum.el

@@ -12522,8 +12522,9 @@ If REVERSE, save parts that do not match TYPE."
                         (not (memq article gnus-newsgroup-cached)))))
     (let ((face (funcall (gnus-summary-highlight-line-0))))
       (unless (eq face (get-text-property beg 'face))
-	(add-face beg (point-at-eol)
-		  (setq face (if (boundp face) (symbol-value face) face)))
+	(gnus-put-text-property-excluding-characters-with-faces
+	 beg (point-at-eol) 'face
+	 (setq face (if (boundp face) (symbol-value face) face)))
 	(when gnus-summary-highlight-line-function
 	  (funcall gnus-summary-highlight-line-function article face))))))
 

lisp/gnus/gnus-util.el

@@ -866,6 +866,19 @@ If there's no subdirectory, delete DIRECTORY as well."
 	  (setq beg (point)))
 	(gnus-overlay-put (gnus-make-overlay beg (point)) prop val)))))
 
+(defun gnus-put-text-property-excluding-characters-with-faces (beg end
+								   prop val)
+  "The same as `put-text-property', but don't put props on characters with the `gnus-face' property."
+  (let ((b beg))
+    (while (/= b end)
+      (when (get-text-property b 'gnus-face)
+	(setq b (next-single-property-change b 'gnus-face nil end)))
+      (when (/= b end)
+	(inline
+	  (gnus-put-text-property
+	   b (setq b (next-single-property-change b 'gnus-face nil end))
+	   prop val))))))
+
 (defmacro gnus-faces-at (position)
   "Return a list of faces at POSITION."
   (if (featurep 'xemacs)