vim-patch:9.0.0816: CTRL-Z at end of file is always dropped

Problem:    CTRL-Z at end of file is always dropped.
Solution:   Add the 'endoffile' option, like the 'endofline' option.
            (closes vim/vim#11408, closes vim/vim#11397)

Cherry-pick test_fixeol.vim changes from patch 8.2.1432.
Cherry-pick 'endoffile' changes from latest Vim runtime update.

fb0cf2357e

vim-patch:f0b567e32a46

Revert unintended Makefile change

f0b567e32a

vim-patch:72c8e3c070b3

Fix wrong struct access for member.

72c8e3c070

vim-patch:3f68a4136eb9

Add missing entry for the 'endoffile' option.

3f68a4136e

Co-authored-by: Bram Moolenaar <Bram@vim.org>

src/nvim/options.lua

@@ -640,6 +640,15 @@ return {
       varname='p_enc',
       defaults={if_true=macros('ENC_DFLT')}
     },
+    {
+      full_name='endoffile', abbreviation='eof',
+      short_desc=N_("write CTRL-Z for last line in file"),
+      type='bool', scope={'buffer'},
+      no_mkrc=true,
+      redraw={'statuslines'},
+      varname='p_eof',
+      defaults={if_true=true}
+    },
     {
       full_name='endofline', abbreviation='eol',
       short_desc=N_("write <EOL> for last line in file"),