bug#64567: 29.0.92; c-ts-mode fails to parse syslogger.c of postgres source

[Eli Zaretskii]

> Date: Tue, 11 Jul 2023 08:30:51 +0800
> From:  Yang Yingchao via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> 1. get source file from
> <https://github.com/postgres/postgres/blob/master/src/backend/postmaster/syslogger.c>
> 1. open it, and move to line 567, then we can see function
> `SysLogger_Start(void)` is not highlighted properly.
> 
> `treesit-explore-mode` shows some error too:
> 
> ```
> (ERROR type: (primitive_type)
>  (function_declarator declarator: (identifier)
>   parameters:
>    (parameter_list (
>     (parameter_declaration type: (primitive_type))
>     )))
> 
> ```
> 
> And when cusor is inside this function, and `treesit-beginning-of-defun`
> will move cusor to `SysLoggerMain()` which is actully the function
> before `SysLogger_Start()`.

It's because of this:


  #ifdef EXEC_BACKEND
          switch ((sysloggerPid = syslogger_forkexec()))
  #else
          switch ((sysloggerPid = fork_process()))
  #endif

The 2 'switch' statements inside preprocessor conditions cause the
parser to fail.  I'm not sure we can do anything with this, except
report this to the developers of the tree-sitter C grammar, but I CC
Yuan and Theo just in case they have some ideas.