Fix erroneous -Werror=missing-braces on old GCC.
In the same spirit as
5e0c761d0 and some earlier commits,
suppress a chorus of buildfarm warnings about braces in
these initializers.
Richard Guo
Discussion: https://postgr.es/m/CAMbWs48GzM-Ff7vr=_CeqaXxFBB9UntqtaW1cjU8hOo62AbOOg@mail.gmail.com