(mark_object): Add debugging code to check for ptr clobbered.

diff --git a/src/alloc.c b/src/alloc.c
index 48117d4..a6f554a 100644 (file)
--- a/src/alloc.c
+++ b/src/alloc.c
@@ -1623,7 +1623,11 @@ mark_object (objptr)
            XUNMARK (obj);
            goto loop;
          }
+       if (ptr == 0)
+         abort ();
        mark_object (&ptr->car);
+       if (ptr == 0)
+         abort ();
        objptr = &ptr->cdr;
        obj = ptr->cdr;
        goto loop;