freeing fports

[Aaron VanDevender]

I noticed that the fport free function doesn't return how much
it frees. This patch should take care of that.

--- libguile.old/fports.c       2003-08-26 23:35:34.000000000 -0500
+++ libguile/fports.c   2003-08-26 23:47:23.000000000 -0500
@@ -827,8 +827,11 @@
 static size_t
 fport_free (SCM port)
 {
+  size_t size;
+  scm_t_port *pt = SCM_PTAB_ENTRY (port);
+  size = pt->read_buf_size + pt->write_buf_size + sizeof(scm_t_fport);
   fport_close (port);
-  return 0;
+  return size;
 }
  
 static scm_t_bits