This patch is needed to allow builds with newer versions of
the GNU libc (2.16+).

The upstream fix was:

  commit 66712c23388e93e5c518ebc8515140fa0c807348
  Author: Eric Blake <eblake@redhat.com>
  Date:   Thu Mar 29 13:30:41 2012 -0600

      stdio: don't assume gets any more

      Gnulib intentionally does not have a gets module, and now that C11
      and glibc have dropped it, we should be more proactive about warning
      any user on a platform that still has a declaration of this dangerous
      interface.

      * m4/stdio_h.m4 (gl_STDIO_H, gl_STDIO_H_DEFAULTS): Drop gets
      support.
      * modules/stdio (Makefile.am): Likewise.
      * lib/stdio-read.c (gets): Likewise.
      * tests/test-stdio-c++.cc: Likewise.
      * m4/warn-on-use.m4 (gl_WARN_ON_USE_PREPARE): Fix comment.
      * lib/stdio.in.h (gets): Make warning occur in more places.
      * doc/posix-functions/gets.texi (gets): Update documentation.
      Reported by Christer Solskogen.

      Signed-off-by: Eric Blake <eblake@redhat.com>

This patch just gets rid of the offending part.

--- m4-1.4.16/lib/stdio.in.h.orig	2012-09-01 01:05:36.000000000 +0200
+++ m4-1.4.16/lib/stdio.in.h	2012-09-01 01:05:42.000000000 +0200
@@ -158,12 +158,6 @@ _GL_WARN_ON_USE (fflush, "fflush is not
                  "use gnulib module fflush for portable POSIX compliance");
 #endif
 
-/* It is very rare that the developer ever has full control of stdin,
-   so any use of gets warrants an unconditional warning.  Assume it is
-   always declared, since it is required by C89.  */
-#undef gets
-_GL_WARN_ON_USE (gets, "gets is a security hole - use fgets instead");
-
 #if @GNULIB_FOPEN@
 # if @REPLACE_FOPEN@
 #  if !(defined __cplusplus && defined GNULIB_NAMESPACE)
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<tr><td><span title='2020-06-02 18:55:53 +0200'>2020-06-02</span></td><td><a href='/guix/commit/README?id=c75a80189fc19f6ff8b4c82d1d1801be6763b6d2'>doc: Update README to refer to the manual.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-11-09 23:04:14 +0100'>2019-11-09</span></td><td><a href='/guix/commit/README?id=0758a70cc008171f31c848128deca9803536fe60'>doc: Mention value /var to localstatedir option.</a><span class='msg-avail'>...</span></td><td>zimoun</td></tr>
<tr><td><span title='2019-09-04 23:41:07 +0200'>2019-09-04</span></td><td><a href='/guix/commit/README?id=f475c6e53e5b6912cc45663d50f1d03dadfb60b8'>doc: Update 'README'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-01-09 14:47:53 +0100'>2019-01-09</span></td><td><a href='/guix/commit/README?id=0991fd53367907908fbd901a9fbe79540e4e4527'>build: Require Guile 2.2.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-12-02 17:56:05 -0600'>2018-12-02</span></td><td><a href='/guix/commit/README?id=6776af04d4b65c5a9a07784307a6abe395b6f480'>Make Guile-JSON a required dependency.</a><span class='msg-avail'>...</span></td><td>Eric Bavier</td></tr>
<tr><td><span title='2018-11-23 15:42:00 +0100'>2018-11-23</span></td><td><a href='/guix/commit/README?id=60e1c1099fc3d73ed7d3235e71aae5d00ab7d773'>Update Guile-SQLite3 URL everywhere.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-09-04 17:25:11 +0200'>2018-09-04</span></td><td><a href='/guix/commit/README?id=ca719424455465fca4b872c371daf2a46de88b33'>Switch to Guile-Gcrypt.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-06-27 16:58:59 +0200'>2018-06-27</span></td><td><a href='/guix/commit/README?id=fc6cbb311c5a1acb9cf1d5422fbf1bc23da31d55'>doc: Specify Guile-SQLite3 minimum version.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-06-14 11:16:58 +0200'>2018-06-14</span></td><td><a href='/guix/commit/README?id=c5a2e1ffcb029f50c4c18352cf378b61c41c625e'>build: Require Guile-SQLite3.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-02-26 18:19:34 +0100'>2018-02-26</span></td><td><a href='/guix/commit/README?id=1d84d7bf6052c0c80bd212d4524876576e9817d4'>build: Require Guile &gt;= 2.0.13.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-01-07 23:47:22 +0100'>2018-01-07</span></td><td><a href='/guix/commit/README?id=06e3a5181efa0ea83bb6608d3cbfba5caa56d7e9'>doc: Mark zlib as mandatory, libbz2 as optional.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2018-01-01 18:21:55 +0100'>2018-01-01</span></td><td><a href='/guix/commit/README?id=397cd9cc416c677e84fb4bb6efef5f99d1d2394f'>doc: Update requirements in 'README'.</a><span class='msg-avail'>...</span></td><td>Mathieu Lirzin</td></tr>
<tr><td><span title='2017-09-25 00:12:49 +0200'>2017-09-25</span></td><td><a href='/guix/commit/README?id=e8d8ecde04a988f04642d754eccc16a14e0cdc53'>README: Replace http:// with https:// where applicable.</a></td><td>Marius Bakke</td></tr>