--- libguile/gc-mark.c.orig	2006-02-12 14:29:12.000000000 +0100
+++ libguile/gc-mark.c	2006-05-05 14:41:07.000000000 +0200
@@ -433,6 +433,8 @@
   for (m = 0; m < n; ++m)
     {
       SCM obj = * (SCM *) &x[m];
+      if ((scm_t_bits)obj & (sizeof (scm_t_cell) - 1))
+        continue;
       long int segment = scm_i_find_heap_segment_containing_object (obj);
       if (segment >= 0)
 	scm_gc_mark (obj);