bug#61558: 29.0.60; Indentation with c-ts-mode doesn't work in code guarded by #ifdef..#endif

[Eli Zaretskii]

> From: Theodor Thornhill <theo@thornhill.no>
> Cc: 61558@debbugs.gnu.org
> Date: Fri, 17 Feb 2023 20:49:23 +0100
> 
> Can you test this patch?  It seems to work for me, but I'm no C expert.

Thanks, this is much better.  However, the handling of #if (as opposed
to #ifdef) is still incorrect.  For example, go to the end of line
3376 of dispnew.c and type RET: point goes to column zero, not column
2.  If you convert "#if" to #ifdef", the behavior becomes correct.
Same problem exists with #elif.

Doesn't tree-sitter grammar consider #if and #elif preprocessor nodes?

Also, there's a problem with #define in the middle of code.  For
example, here:

  /* Put a `display' property on the string for the captions to display,
     put a `menu_item' property on tab-bar items with a value that
     is the index of the item in F's tab-bar item vector.  */
  for (i = 0; i < f->n_tab_bar_items; ++i)
    {
#define PROP(IDX) \
  AREF (f->tab_bar_items, i * TAB_BAR_ITEM_NSLOTS + (IDX))

      caption = Fcopy_sequence (PROP (TAB_BAR_ITEM_CAPTION));  <<<<<<<<<<

      /* Put a `display' text property on the string for the caption to
         display.  Put a `menu-item' property on the string that gives
         the start of this item's properties in the tab-bar items
         vector.  */
      AUTO_LIST2 (props, Qmenu_item, make_fixnum (i * TAB_BAR_ITEM_NSLOTS));

      Fadd_text_properties (make_fixnum (0), make_fixnum (SCHARS (caption)),
                            props, caption);

      f->desired_tab_bar_string =
        concat2 (f->desired_tab_bar_string, caption);

#undef PROP <<<<<<<<<<<<<<<<<<<<
    }

Typing RET at the end of the two marked lines goes to column zero
instead of the expected non-zero column.  So it sounds like #define
and #undef are also not handled correctly yet.