* gnu/packages/base.scm (glibc@2.27)[sources]: Add patches. [properties]: New field, mark CVE-2017-18269 fixed. * gnu/packages/patches/glibc-CVE-2018-11236.patch, gnu/packages/patches/glibc-CVE-2018-11237.patch: New files. * gnu/local.mk (dist_patch_DATA): Register them.