Fix whitespace highlighting of context diffs.

* lisp/vc/diff-mode.el (diff-setup-whitespace): New function.
(diff-mode): Use it.

* lisp/vc/diff.el (diff-sentinel):
* lisp/vc/vc.el (vc-diff-finish): Call diff-setup-whitespace to assign
Whitespace mode variables based on diff style.

Fixes: debbugs:8612

1 files changed, 3 insertions, 0 deletions

diff --git a/lisp/vc/diff.el b/lisp/vc/diff.el
index 05208894356..dd4b4757e88 100644
--- a/lisp/vc/diff.el
+++ b/lisp/vc/diff.el
@@ -30,6 +30,8 @@
 
 ;;; Code:
 
+(declare-function diff-setup-whitespace "diff-mode" ())
+
 (eval-when-compile (require 'cl))
 
 (defgroup diff nil
@@ -64,6 +66,7 @@ If optional args OLD-TEMP-FILE and/or NEW-TEMP-FILE are non-nil,
 delete the temporary files so named."
   (if old-temp-file (delete-file old-temp-file))
   (if new-temp-file (delete-file new-temp-file))
+  (diff-setup-whitespace)
   (save-excursion
     (goto-char (point-max))
     (let ((inhibit-read-only t))