Patch syntax coloring for xemacs / XP

[smd <sssmmmddd@gmail.com>]

This took me forever to find :) I am a total newb, and wanted to use
the facilities of Emacs that allow for editing of diff patch files
(like hunk row calculations, etc)... As soon as I installed the latest
version, and opened a patch file, and chosen font-lock-mode (I guess
the syntax coloring mode), I could see that *only* the patch headers
are colored, but not the added/removed files (i.e. those starting with
+ / - in a patch file). (As I also messed up the diff-mode display, ow
I als have to start it by using Alt-X, then type "diff-mode" and
Enter, an say no to "convert contents back to binary format").

Once you're sure you're in diff-mode, and syntax-coloring is on, heres
how to get those rows to color:
- Options / Edit Faces...
- scroll down, and find Diff Added Face, and Diff Changed Face, and
change those by clicking the little trangle, clicking the box next to
Foreground/Background in the subsequently opened options, and type in
a color like 'red', preview will be enabled
--- Note that these options (Diff Added Face) will NOT be present,
unless diff-mode is currently active
--- notice that Diff Context Face should already be defaulted to a
gray color
- to save, right click, select Save

After this, the patch should have th lines correspondingly colored.
This process should make a file, custom.el, with the following
contents:
(custom-set-variables)
(custom-set-faces
 '(diff-added-face ((t (:foreground "red"))))
 '(diff-changed-face ((t (:foreground "darkorange"))))
 '(diff-removed-face ((t (:foreground "blue")))))

However, it seems these options do not get saved with xemacs, so I
have to re-do the procedure each time I start it...