gnu: glibc: Add mitigations for CVE-2017-1000366.

gnu: glibc: Add mitigations for CVE-2017-1000366.

* gnu/packages/base.scm (glibc/linux)[replacement]: New field.
(glibc-2.25-patched): New variable.
(glibc-2.24, glibc-2.23, glibc-2.22, glibc-2.21)[source]: Add patches.
[replacement]: New field.
(glibc-locales)[replacement]: New field.
* gnu/packages/patches/glibc-CVE-2017-1000366-pt1.patch,
gnu/packages/patches/glibc-CVE-2017-1000366-pt2.patch,
gnu/packages/patches/glibc-CVE-2017-1000366-pt3.patch: New files.
* gnu/local.mk (dist_patch_DATA): Add them.

Modified-By: Mark H Weaver <mhw@netris.org>