Olá Fórum,
Quando eu usava o comando "python manage.py makemessages -l pt_BR" houve o seguinte erro, CommandError: Can't find msguniq. Make sure you have GNU gettext tools 0.15 or newer installed.
Consegui resolver instalando o gettext: sudo apt-get install gettext
Outras opções: https://stackoverflow.com/questions/35101850/cant-find-msguniq-make-sure-you-have-gnu-gettext-tools-0-15-or-newer-installed
Espero ter ajudado.
