gettext

5b36b041 - build: Ensure that makeinfo ≥ 6.8 checks the @menu structure.

build: Ensure that makeinfo ≥ 6.8 checks the @menu structure. See <https://lists.gnu.org/archive/html/bug-texinfo/2023-06/msg00015.html>. * gettext-tools/doc/Makefile.am (MAKEINFO): Add option "-c CHECK_NORMAL_MENU_STRUCTURE=1".