bug#48264: [PATCH v3 12/15] Set buffer_defaults fields without a default to Qunbound

[Spencer Baugh <sbaugh@catern.com>]

Eli Zaretskii <eliz@gnu.org> writes:
>> From: Spencer Baugh <sbaugh@catern.com>
>> Cc: 48264@debbugs.gnu.org
>> Date: Fri, 07 May 2021 10:15:14 -0400
>> 
>> >> The syntax_table and category_table fields in buffer_defaults are used
>> >> through Vstandard_syntax_table and Vstandard_category_table (which are
>> >> just aliases to the fields in buffer_defaults); the initialization for
>> >> syntax.c and category.c runs before buffer.c, so they're already set at
>> >> this point.  I could reorder the initialization if you'd prefer that?
>> >> Or move the initialization into buffer.c?
>> >
>> > If it works to move init_buffer_once before init_syntax_once, I think
>> > that'd be much better.
>> 
>> Hm, regrettably, it doesn't seem to be as simple as that; doing so
>> causes failures in dumping.  I now remember that I tried this before and
>> had much difficulty doing this by reordering the intialization.
>> 
>> I could try moving the initialization into buffer.c?
>
> Maybe making the Vstandard_syntax_table setup a separate function in
> syntax.c, and then calling it from init_buffer_once?  IOW, leave only
> the creation of Vstandard_syntax_table in init_syntax_once, and doing
> the rest in init_buffer_once?  Does that work?

OK, in the end I was able to get moving init_{syntax,category}_once
after init_buffer_once to work, by initializing the two variables to
Qnil in buffer.c.  I assume it wasn't working before because they were
Qunbound rather than Qnil, and something is checking NILP to see if the
variables are initialized. (Although not sure what).

So, I was able to remove the special case.