patch 8.0.0655: not easy to make sure a function does not exist commit https://github.com/vim/vim/commit/d6abcd154cdc6a8dd4b7c6ccad37617ea8a1b4aa Author: Bram Moolenaar <Bram@vim.org> Date: Thu Jun 22 19:15:24 2017 +0200 patch 8.0.0655: not easy to make sure a function does not exist Problem: Not easy to make sure a function does not exist. Solution: Add ! as an optional argument to :delfunc.

" vimrc for test_gui_init.vim

" Note that this flag must be added in the .vimrc file, before switching on
" syntax or filetype recognition (when the |gvimrc| file is sourced the system
" menu has already been loaded; the ":syntax on" and ":filetype on" commands
" load the menu too).
set guioptions+=M