Fix CVE-2019-19126:

https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-19126
https://sourceware.org/bugzilla/show_bug.cgi?id=25204

Taken from upstream:
https://sourceware.org/git/?p=glibc.git;a=commit;h=37c90e117310728a4ad1eb998c0bbe7d79c4a398

diff --git a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
index 975cbe2..df2cdfd 100644
--- a/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
+++ b/sysdeps/unix/sysv/linux/x86_64/64/dl-librecon.h
@@ -31,7 +31,8 @@
    environment variable, LD_PREFER_MAP_32BIT_EXEC.  */
 #define EXTRA_LD_ENVVARS \
   case 21:								  \
-    if (memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0)		  \
+    if (!__libc_enable_secure						  \
+	&& memcmp (envline, "PREFER_MAP_32BIT_EXEC", 21) == 0)		  \
       GLRO(dl_x86_cpu_features).feature[index_arch_Prefer_MAP_32BIT_EXEC] \
 	|= bit_arch_Prefer_MAP_32BIT_EXEC;				  \
     break;
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<div class='path'>path: <a href='/guix/log/?id=d15ffea6f47a40a9d36f3f32935e63f92e90af03'>root</a>/<a href='/guix/log/gnu?id=d15ffea6f47a40a9d36f3f32935e63f92e90af03'>gnu</a>/<a href='/guix/log/gnu/bootloader?id=d15ffea6f47a40a9d36f3f32935e63f92e90af03'>bootloader</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/bootloader?id=d15ffea6f47a40a9d36f3f32935e63f92e90af03&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-07-13 18:59:13 +0200'>2023-07-13</span></td><td><a href='/guix/commit/gnu/bootloader?id=c22c29b0c4821ebe2c66a6c76562a41d33ff8392'>bootloader: grub: Use rumpdisk-style root when booting with "noide".</a></td><td>Janneke Nieuwenhuizen</td></tr>
<tr><td><span title='2023-06-14 14:52:21 +0300'>2023-06-14</span></td><td><a href='/guix/commit/gnu/bootloader?id=39250fc6229d60b7ae397749caf1e4c99e49b419'>gnu: bootloader: Add u-boot-sifive-unmatched-bootloader.</a></td><td>Efraim Flashner</td></tr>
<tr><td><span title='2023-01-18 21:25:25 -0500'>2023-01-18</span></td><td><a href='/guix/commit/gnu/bootloader?id=9530ee9f9c89cbbf35589727e9fdb373ed7f47fa'>gnu: Add u-boot-ts7970-q-2g-1000mhz-c-bootloader.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-12-28 22:14:16 -0500'>2022-12-28</span></td><td><a href='/guix/commit/gnu/bootloader?id=d6ea9f8b38df7de1194d8106488a8c33cce64fd1'>gnu: u-boot-am335x-boneblack: Revert to old name.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-12-20 21:29:25 -0500'>2022-12-20</span></td><td><a href='/guix/commit/gnu/bootloader?id=c04528d2a2597d79278833f3607c806278253446'>gnu: u-boot-am335x-evm-boneblack: Fix variable name.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-12-07 23:19:56 -0500'>2022-12-07</span></td><td><a href='/guix/commit/gnu/bootloader?id=f76ed96f934fc83bb0f974396941c6a90a90e9fc'>bootloaders: grub: Fix comment.</a></td><td>Maxim Cournoyer</td></tr>
<tr><td><span title='2022-12-01 14:31:28 -0500'>2022-12-01</span></td><td><a href='/guix/commit/gnu/bootloader?id=a9acbf919a7668e26863d2d26d48c5fd41b57fcd'>gnu: bootloader: Rework chaining, add grub-efi-netboot-removable-bootloader.</a></td><td>Stefan</td></tr>
<tr><td><span title='2022-09-08 22:30:09 +0200'>2022-09-08</span></td><td><a href='/guix/commit/gnu/bootloader?id=1fc20e4c86697e9d112b9fed8079334c818dd78e'>gnu: bootloader: grub: Add support for chain-loader.</a></td><td>tiantian</td></tr>
<tr><td><span title='2022-08-30 08:50:44 +0200'>2022-08-30</span></td><td><a href='/guix/commit/gnu/bootloader?id=f126f23b132148192b2c9a89032a5831af0b3c52'>bootloader: Add device-tree-support? option.</a></td><td>Reza Alizadeh Majd</td></tr>
<tr><td><span title='2022-06-24 10:21:06 +0200'>2022-06-24</span></td><td><a href='/guix/commit/gnu/bootloader?id=62c86c8391ceb8953ca972498fd75ea9298b85ff'>image: Add support for 32bit UEFI.</a></td><td>Denis 'GNUtoo' Carikli</td></tr>
<tr><td><span title='2022-06-06 22:43:30 +0200'>2022-06-06</span></td><td><a href='/guix/commit/gnu/bootloader?id=618f665a5ffc6330bc99c4ac2b1077c1e1a7506c'>bootloader: grub: Add removable grub-efi bootloader option.</a></td><td>Karl Hallsby</td></tr>
<tr><td><span title='2022-01-13 11:11:02 +0100'>2022-01-13</span></td><td><a href='/guix/commit/gnu/bootloader?id=ea71ec1630e06503c14c6e7f4570b69de4e42123'>bootloader: grub: Fix serial mode.</a></td><td>Mathieu Othacehe</td></tr>
<tr><td><span title='2021-12-01 17:51:37 +0100'>2021-12-01</span></td><td><a href='/guix/commit/gnu/bootloader?id=adce91a3ec0cb2912daa6eefe9324c15ff3126f7'>gnu: system: Add LUKS2 support for the root file system.</a></td><td>Josselin Poiret</td></tr>
<tr><td><span title='2021-08-29 01:05:26 -0400'>2021-08-29</span></td><td><a href='/guix/commit/gnu/bootloader?id=da4e40948326387d5bcda58783914d5f9ce8b095'>Migrate to the new 'targets' field of bootloader-configuration.</a></td><td>Maxim Cournoyer</td></tr>