Merge branch 'ab/dynamic-gettext-poison'

Our testing framework uses a special i18n "poisoned localization" feature to find messages that ought to stay constant but are incorrectly marked to be translated. This feature has been made into a runtime option (it used to be a compile-time option). * ab/dynamic-gettext-poison: Makefile: ease dynamic-gettext-poison transition i18n: make GETTEXT_POISON a runtime option