Revert "Avoid infinite recursion in 'window_wants_header_line'"

This reverts commit 3de8ed09ab46b9922e15aaf0cc8884b41087c996.
This is part of removing the recently-added feature whereby
certain non-nil values of 'header-line-format' could signal
that the header line shall not be displayed.  The feature is
being reverted because its advantages are very minor, whereas
the complications it causes are serious.

diff --git a/src/window.c b/src/window.c
index fa024b6d2d8f2a365350c9527fdbbb85ad7e7b9b..e56dad63a7006aef517cb9148e396f8bcdfdf217 100644 (file)
--- a/src/window.c
+++ b/src/window.c
@@ -5469,7 +5469,6 @@ window_wants_mode_line (struct window *w)
          && WINDOW_PIXEL_HEIGHT (w) > WINDOW_FRAME_LINE_HEIGHT (w));
 }
 
-static int header_line_eval_called = 0;
 
 /**
  * null_header_line_format:
@@ -5497,18 +5496,9 @@ null_header_line_format (Lisp_Object fmt, struct frame *f)
        {
          if (EQ (car, QCeval))
            {
-             if (header_line_eval_called > 0)
-               return false;
-             eassert (header_line_eval_called == 0);
-             header_line_eval_called++;
              val = safe_eval_inhibit_quit (XCAR (XCDR (fmt)));
-             header_line_eval_called--;
-             eassert (header_line_eval_called == 0);
              if (!FRAME_LIVE_P (f))
-               {
-                 header_line_eval_called = 0;
-                 signal_error (":eval deleted the frame being displayed", fmt);
-               }
+               signal_error (":eval deleted the frame being displayed", fmt);
              return NILP (val);
            }
          val = find_symbol_value (car);