Update libgcrypt and remove reproducibility patch, it is now built-in.
See https://dev.gnupg.org/T4102

* gnu/packages/gnupg.scm (libgcrypt): Update to 1.8.4.
[source]: Remove patch.
* gnu/packages/patches/libgcrypt-make-yat2m-reproducible.patch: Delete file.
* gnu/local.mk(dist_patch_DATA): Remove it.
---
 gnu/local.mk                                  |  1 -
 gnu/packages/gnupg.scm                        |  7 ++--
 .../libgcrypt-make-yat2m-reproducible.patch   | 32 -------------------
 3 files changed, 3 insertions(+), 37 deletions(-)
 delete mode 100644 gnu/packages/patches/libgcrypt-make-yat2m-reproducible.patch

diff --git a/gnu/local.mk b/gnu/local.mk
index 4ba49e86a..ce45c64ec 100644
--- a/gnu/local.mk
+++ b/gnu/local.mk
@@ -885,7 +885,6 @@ dist_patch_DATA =						\
   %D%/packages/patches/libevent-2.1-skip-failing-test.patch	\
   %D%/packages/patches/libexif-CVE-2016-6328.patch		\
   %D%/packages/patches/libexif-CVE-2017-7544.patch		\
-  %D%/packages/patches/libgcrypt-make-yat2m-reproducible.patch	\
   %D%/packages/patches/libgit2-mtime-0.patch			\
   %D%/packages/patches/libgdata-fix-tests.patch			\
   %D%/packages/patches/libgdata-glib-duplicate-tests.patch	\
diff --git a/gnu/packages/gnupg.scm b/gnu/packages/gnupg.scm
index 3d6727bbd..0b8d3e578 100644
--- a/gnu/packages/gnupg.scm
+++ b/gnu/packages/gnupg.scm
@@ -15,6 +15,7 @@
 ;;; Copyright © 2017 Petter <petter@mykolab.ch>
 ;;; Copyright © 2018 Tobias Geerinckx-Rice <me@tobias.gr>
 ;;; Copyright © 2018 Marius Bakke <mbakke@fastmail.com>
+;;; Copyright © 2018 Björn Höfling <bjoern.hoefling@bjoernhoefling.de>
 ;;;
 ;;; This file is part of GNU Guix.
 ;;;
@@ -97,16 +98,14 @@ Daemon and possibly more in the future.")
 (define-public libgcrypt
   (package
     (name "libgcrypt")
-    (version "1.8.3")
+    (version "1.8.4")
     (source (origin
              (method url-fetch)
              (uri (string-append "mirror://gnupg/libgcrypt/libgcrypt-"
                                  version ".tar.bz2"))
              (sha256
               (base32
-               "0z5gs1khzyknyfjr19k8gk4q148s6q987ya85cpn0iv70fz91v36"))
-             (patches
-              (search-patches "libgcrypt-make-yat2m-reproducible.patch"))))
+               "09r27ywj9zplq6n9qw3mn7zmvf6y2jdmwx5d1kg8yqkj0qx18f7n"))))
     (build-system gnu-build-system)
     (propagated-inputs
      `(("libgpg-error-host" ,libgpg-error)))
diff --git a/gnu/packages/patches/libgcrypt-make-yat2m-reproducible.patch b/gnu/packages/patches/libgcrypt-make-yat2m-reproducible.patch
deleted file mode 100644
index 3056f0baa..000000000
--- a/gnu/packages/patches/libgcrypt-make-yat2m-reproducible.patch
+++ /dev/null
@@ -1,32 +0,0 @@
-Make yat2m in libgcrypt respect SOURCE_DATE_EPOCH, making
-the build reproducible.
-
-This was already fixed upstream in GnuPG:
-https://dev.gnupg.org/rG139de02b93773615bdd95e04a7f0c1ad73b4f6fb
-
-and in libgpg-error:
-https://dev.gnupg.org/rE5494a5728418938d2e42158bb646b07124184e64
-
-
---- a/doc/yat2m.c 2017-11-23 19:16:58.000000000 +0100
-+++ b/doc/yat2m.c 2017-08-28 12:22:54.000000000 +0200
-@@ -1475,6 +1484,7 @@
- main (int argc, char **argv)
- {
-   int last_argc = -1;
-+  const char *s;
- 
-   opt_source = "GNU";
-   opt_release = "";
-@@ -1608,6 +1618,11 @@
-   if (argc > 1)
-     die ("usage: " PGM " [OPTION] [FILE] (try --help for more information)\n");
- 
-+  /* Take care of supplied timestamp for reproducible builds.  See
-+   * https://reproducible-builds.org/specs/source-date-epoch/  */
-+  if (!opt_date && (s = getenv ("SOURCE_DATE_EPOCH")) && *s)
-+    opt_date = s;
-+
-   /* Start processing. */
-   if (argc && strcmp (*argv, "-"))
-     {
-- 
2.19.1