vim-patch:9.0.0819: still a build error, tests are failing

Problem:    Still a build error, tests are failing.
Solution:   Correct recent changes. Add missing init for 'eof'.

1577537f10

vim-patch:1577537f109d

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

src/nvim/buffer_defs.h

@@ -794,6 +794,7 @@ struct file_buffer {
   linenr_T b_no_eol_lnum;       // non-zero lnum when last line of next binary
                                 // write should not have an end-of-line
 
+  int b_start_eof;              // last line had eof (CTRL-Z) when it was read
   int b_start_eol;              // last line had eol when it was read
   int b_start_ffc;              // first char of 'ff' when edit started
   char *b_start_fenc;           // 'fileencoding' when edit started or NULL