patch 8.2.2159: Vim9: when declaring a list it is not allocated yet Commit: https://github.com/vim/vim/commit/3beaf9cd8efa3ba83e07187215004d140b89d529 Author: Bram Moolenaar <Bram@vim.org> Date: Fri Dec 18 17:23:14 2020 +0100 patch 8.2.2159: Vim9: when declaring a list it is not allocated yet Problem: Vim9: when declaring a list it is not allocated yet, causing a following extend() to fail. Solution: When fetching a variable value for a list or dict that is null allocate the list or dict, so it can be used. (closes #7491)

/^CFLAGS[[:blank:]]*=/s/$/ -Wall -Wextra -Wshadow -Werror/
/^PERL_CFLAGS[[:blank:]]*=/s/$/ -Wno-error=unused-function/