patch 8.1.0067: syntax highlighting not working when re-entering a bu…

…ffer

Problem:    Syntax highlighting not working when re-entering a buffer.
Solution:   Do force executing autocommands when not called recursively.

src/option.c

@@ -7567,24 +7567,32 @@ did_set_string_option(
	/* When 'syntax' is set, load the syntax of that name */
	if (varp == &(curbuf->b_p_syn))
	{
	    // Only pass TRUE for "force" when the value changed, to avoid
	    // endless recurrence. */
	    apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn,
				       curbuf->b_fname, value_changed, curbuf);
	    static int syn_recursive = 0;

	    ++syn_recursive;
	    // Only pass TRUE for "force" when the value changed or not used
	    // recursively, to avoid endless recurrence.
	    apply_autocmds(EVENT_SYNTAX, curbuf->b_p_syn, curbuf->b_fname,
		    value_changed || syn_recursive == 1, curbuf);
	    --syn_recursive;
	}
#endif
	else if (varp == &(curbuf->b_p_ft))
	{
	    /* 'filetype' is set, trigger the FileType autocommand.
	     * Skip this when called from a modeline and the filetype was
	     * already set to this value.
	     * Only pass TRUE for "force" when the value changed, to avoid
	     * endless recurrence. */
	     * already set to this value. */
	    if (!(opt_flags & OPT_MODELINE) || value_changed)
	    {
		static int ft_recursive = 0;

		++ft_recursive;
		did_filetype = TRUE;
		apply_autocmds(EVENT_FILETYPE, curbuf->b_p_ft,
				       curbuf->b_fname, value_changed, curbuf);
		// Only pass TRUE for "force" when the value changed or not
		// used recursively, to avoid endless recurrence.
		apply_autocmds(EVENT_FILETYPE, curbuf->b_p_ft, curbuf->b_fname,
				   value_changed || ft_recursive == 1, curbuf);
		--ft_recursive;
		/* Just in case the old "curbuf" is now invalid. */
		if (varp != &(curbuf->b_p_ft))
		    varp = NULL;

src/version.c

@@ -761,6 +761,8 @@ static char *(features[]) =

static int included_patches[] =
{   /* Add new patch number below this line */
/**/
    67,
/**/
    66,
/**/