The `localedef` tool expects `/usr/lib/locale` directory to
exist. This directory used to be created by the `sys-libs/glibc`
package (with the `keepdir` directive), but after the update of the
package, the locale generation stuff (and the `keepdir` directive )was
moved to the `sys-libs/locale-gen` package. This package is not
installed in the production images, so the `/usr/lib/locale` directory
was not created. In such a situation, calling localedef to generate
C.UTF-8 locale resulted in an error like:
cannot create temporary file: ${SOME_ROOTFS}/usr/lib/locale/locale-archive.ufpG15: No such file or directory
Create the directory before calling localedef to fix the problem.