patch 8.0.1744: on some systems /dev/stdout isn't writable commit https://github.com/vim/vim/commit/9980b37a80dc72eef05bf8862aaf475ab17790a5 Author: Bram Moolenaar <Bram@vim.org> Date: Sat Apr 21 20:12:35 2018 +0200 patch 8.0.1744: on some systems /dev/stdout isn't writable Problem: On some systems /dev/stdout isn't writable. Solution: Skip test if writing is not possible. (James McCoy, closes https://github.com/vim/vim/issues/2830)