This fixes some fun type size truncation that shows up giving errors like
" changes value from '287948901175001088' to '0' "

.. which turns out is a known issue with later gcc's.

eg - https://lists.gnu.org/archive/html/bug-gnulib/2012-03/msg00154.html

It was fixed up upstream corelib/gnulib in commit hash
252b52457da7887667c036d18cc5169777615bb0
(eg in https://github.com/coreutils/gnulib/commit/252b52457da7887667c036d18cc5169777615bb0)

TEST PLAN

• compiled/run for gcc-6.4 on amd64

Reviewed by: imp
Differential Revision: https://reviews.freebsd.org/D26804