Debian and Archlinux (at least) force the installation of the
localedata/SUPPORTED file of the glibc. This file lists all the supported
locales of the glibc.
* gnu/packages/patches/glibc-supported-locales.patch: New file.
* gnu/local.mk (dist_patch_DATA): Add it.
* gnu/packages/base.scm (glibc/linux): Add the previous patch,
(glibc-2.28): ditto.
Mathieu Othacehe