patch 8.1.1653: ubsan warns for possibly passing NULL pointer commit https://github.com/vim/vim/commit/0d07155c8bbaca1a527b79da358438253a60839f Author: Bram Moolenaar <Bram@vim.org> Date: Mon Jul 8 22:04:03 2019 +0200 patch 8.1.1653: ubsan warns for possibly passing NULL pointer Problem: Ubsan warns for possibly passing NULL pointer. Solution: Skip code when length is zero. (Dominique Pelle, closes https://github.com/vim/vim/issues/4631)