bug#26247: Gettext introduces timestamps in .mo files

[Ludovic Courtès]

Gettext 0.19.8.1 (current core-updates,
77ab6983a19ef307558ab2607920158d6bb94ba8) introduces timestamps in .mo
file, without honoring SOURCE_DATE_EPOCH, which leads to
non-reproducible builds (for example ‘guix’).

Ludo’.