emacs-31 422bf368477: Minor fix for 'format-mode-line'

branch: emacs-31
commit 422bf368477921a91000f72e759894acd1e4acd3
Author: Eli Zaretskii <[email protected]>
Commit: Eli Zaretskii <[email protected]>

    Minor fix for 'format-mode-line'
    
    * src/xdisp.c (Fformat_mode_line): Treat 'default' exactly like
    nil.  (Bug#81307)
---
 src/xdisp.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/xdisp.c b/src/xdisp.c
index 5080c5253a4..2f02d9faa76 100644
--- a/src/xdisp.c
+++ b/src/xdisp.c
@@ -29040,6 +29040,8 @@ are the selected window and the WINDOW's buffer).  */)
     face = EQ (window, selected_window)
       ? Qmode_line_active
       : Qmode_line_inactive;
+  else if (EQ (face, Qdefault))
+    face = Qnil;
 
   old_buffer = current_buffer;