gnu: oath-toolkit: Fix FTBFS with Glibc >= 2.28.

* gnu/packages/patches/oath-toolkit-glibc-compat.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/authentication.scm (oath-toolkit)[source](patches): New field.

gnu/local.mk

@@ -994,6 +994,7 @@ dist_patch_DATA =						\
   %D%/packages/patches/nvi-db4.patch				\
   %D%/packages/patches/nyacc-binary-literals.patch		\
   %D%/packages/patches/nyx-show-header-stats-with-python3.patch	\
+  %D%/packages/patches/oath-toolkit-glibc-compat.patch		\
   %D%/packages/patches/ocaml-bisect-fix-camlp4-in-another-directory.patch	\
   %D%/packages/patches/ocaml-bitstring-fix-configure.patch \
   %D%/packages/patches/ocaml-CVE-2015-8869.patch		\

gnu/packages/authentication.scm

@@ -17,6 +17,7 @@
 ;;; along with GNU Guix.  If not, see <http://www.gnu.org/licenses/>.
 
 (define-module (gnu packages authentication)
+  #:use-module (gnu packages)
   #:use-module (gnu packages linux)
   #:use-module (gnu packages pkg-config)
   #:use-module (guix build-system gnu)
@@ -35,6 +36,7 @@
        (method url-fetch)
        (uri (string-append "https://download.savannah.nongnu.org/releases/"
                            name "/" name "-" version ".tar.gz"))
+       (patches (search-patches "oath-toolkit-glibc-compat.patch"))
        (sha256
         (base32 "182ah8vfbg0yhv6mh1b6ap944d0na6x7lpfkwkmzb6jl9gx4cd5h"))))
     (build-system gnu-build-system)

gnu/packages/patches/oath-toolkit-glibc-compat.patch

@@ -0,0 +1,90 @@
+Adjust the bundled Gnulib to cope with removal of libio interface in Glibc 2.28.
+
+Based on this upstream gnulib patch:
+https://git.savannah.gnu.org/cgit/gnulib.git/commit/?id=4af4a4a71827c0bc5e0ec67af23edef4f15cee8e
+
+--- a/liboath/gl/fflush.c
++++ b/liboath/gl/fflush.c
+@@ -33,7 +33,7 @@
+ #undef fflush
+ 
+ 
+-#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
++#if defined _IO_EOF_SEEN || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+ 
+ /* Clear the stream's ungetc buffer, preserving the value of ftello (fp).  */
+ static void
+@@ -72,7 +72,7 @@
+ 
+ #endif
+ 
+-#if ! (defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */)
++#if ! (defined _IO_EOF_SEEN  || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */)
+ 
+ # if (defined __sferror || defined __DragonFly__ || defined __ANDROID__) && defined __SNPT
+ /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Android */
+@@ -148,7 +148,7 @@
+   if (stream == NULL || ! freading (stream))
+     return fflush (stream);
+ 
+-#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
++#if defined _IO_EOF_SEEN || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+ 
+   clear_ungetc_buffer_preserving_position (stream);
+ 
+--- a/liboath/gl/fpurge.c
++++ b/liboath/gl/fpurge.c
+@@ -62,7 +62,7 @@
+   /* Most systems provide FILE as a struct and the necessary bitmask in
+      <stdio.h>, because they need it for implementing getc() and putc() as
+      fast macros.  */
+-# if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
++#if defined _IO_EOF_SEEN || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+   fp->_IO_read_end = fp->_IO_read_ptr;
+   fp->_IO_write_ptr = fp->_IO_write_base;
+   /* Avoid memory leak when there is an active ungetc buffer.  */
+--- a/libaoth/gl/freading.c
++++ b/liboath/gl/freading.c
+@@ -31,7 +31,7 @@
+   /* Most systems provide FILE as a struct and the necessary bitmask in
+      <stdio.h>, because they need it for implementing getc() and putc() as
+      fast macros.  */
+-# if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
++#if defined _IO_EOF_SEEN || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+   return ((fp->_flags & _IO_NO_WRITES) != 0
+           || ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
+               && fp->_IO_read_base != NULL));
+--- a/liboath/gl/fseeko.c
++++ b/liboath/gl/fseeko.c
+@@ -47,7 +47,7 @@
+ #endif
+ 
+   /* These tests are based on fpurge.c.  */
+-#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
++#if defined _IO_EOF_SEEN  || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+   if (fp->_IO_read_end == fp->_IO_read_ptr
+       && fp->_IO_write_ptr == fp->_IO_write_base
+       && fp->_IO_save_base == NULL)
+@@ -123,7 +123,7 @@
+           return -1;
+         }
+ 
+-#if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
++#if defined _IO_EOF_SEEN  || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
+       fp->_flags &= ~_IO_EOF_SEEN;
+       fp->_offset = pos;
+ #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
+--- a/liboath/gl/stdio-impl.h
++++ b/liboath/gl/stdio-impl.h
+@@ -18,6 +18,11 @@
+    the same implementation of stdio extension API, except that some fields
+    have different naming conventions, or their access requires some casts.  */
+ 
++/* Glibc 2.28 made _IO_IN_BACKUP private, so define it here for now.  */
++#if !defined _IO_IN_BACKUP && defined _IO_EOF_SEEN
++# define _IO_IN_BACKUP 0x100
++#endif
++
+ /* BSD stdio derived implementations.  */
+ 
+ #if defined __NetBSD__                         /* NetBSD */