gnu: Add emacs-undohist-el.

* gnu/packages/patches/emacs-undohist-ignored.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add this.
* gnu/packages/emacs-xyz.scm (emacs-undohist-el): New variable.

Signed-off-by: Oleg Pykhalov <go.wigust@gmail.com>

gnu/local.mk

@@ -751,6 +751,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/emacs-scheme-complete-scheme-r5rs-info.patch	\
   %D%/packages/patches/emacs-source-date-epoch.patch		\
   %D%/packages/patches/emacs-realgud-fix-configure-ac.patch	\
+  %D%/packages/patches/emacs-undohist-ignored.patch	\
   %D%/packages/patches/emacs-wordnut-require-adaptive-wrap.patch	\
   %D%/packages/patches/emacs-zones-called-interactively.patch	\
   %D%/packages/patches/enlightenment-fix-setuid-path.patch	\

gnu/packages/emacs-xyz.scm

@@ -4535,6 +4535,29 @@ Emacs default configuration in uncontroversial ways that nearly everyone can
 agree upon.")
     (license license:gpl3+)))
 
+(define-public emacs-undohist-el
+  (let ((commit "d2239a5f736724ceb9e3b6bcaa86f4064805cda0")
+        (revision "1"))
+    (package
+      (name "emacs-undohist-el")
+      (version (git-version "0" revision commit))
+      (source
+       (origin
+         (method git-fetch)
+         (uri (git-reference
+               (url "https://github.com/m2ym/undohist-el")
+               (commit commit)))
+         (file-name (git-file-name name version))
+         (sha256
+          (base32
+           "1c0daw246ky7b1x5b8h55x79pl1pjqk1k348l487bdd8zdj4w9wx"))))
+      (build-system emacs-build-system)
+      (home-page "https://github.com/m2ym/undohist-el")
+      (synopsis "Save undo history between sessions")
+      (description "This package allows persistent use of undo history for
+individual file buffers.")
+      (license license:gpl3+))))
+
 (define-public emacs-eprime
   (let ((commit "17a481af26496be91c07139a9bfc05cfe722506f"))
     (package

gnu/packages/patches/emacs-undohist-ignored.patch

@@ -0,0 +1,27 @@
+From 52bfd419bf9022726048f818d955b8ea10a16d5c Mon Sep 17 00:00:00 2001
+From: Patrick Mosby <info@schreiblogade.de>
+Date: Mon, 7 Sep 2015 09:05:56 +0200
+Subject: [PATCH] Don't save undo file for ignored files.
+
+This fixes #4.
+---
+ undohist.el | 3 ++-
+ 1 file changed, 2 insertions(+), 1 deletion(-)
+
+diff --git a/undohist.el b/undohist.el
+index b184a26..de60356 100644
+--- a/undohist.el
++++ b/undohist.el
+@@ -164,7 +164,8 @@ To use undohist, you just call this function."
+                 undohist-ignored-files)))
+ 
+ (defun undohist-save-1 ()
+-  (when (consp buffer-undo-list)
++  (when (and (consp buffer-undo-list)
++             (undohist-recover-file-p (buffer-file-name (current-buffer))))
+     (let ((file (make-undohist-file-name (buffer-file-name)))
+           (contents `((digest . ,(md5 (current-buffer)))
+                       (undo-list . ,(undohist-encode buffer-undo-list)))))
+-- 
+2.21.0
+