More fixes in libmu_scm.

* libmu_scm/mu_mailbox.c (mu-mailbox-get-port): Fix return value.
* libmu_scm/mu_port.c (mu_port_flush): Avoid warnings on passing
arg 2 to mu_stream_write.
(mu_port_free): Return 0.
* libmu_scm/mu_message.c (mu_scm_message_free): Return 0.

@@ -304,6 +304,7 @@ SCM_DEFINE (scm_mu_mailbox_get_port, "mu-mailbox-get-port", 2, 0, 0,
   mu_stream_t stream;
   int status;
   char *s;
+  SCM ret;
   
   SCM_ASSERT (mu_scm_is_mailbox (MBOX), MBOX, SCM_ARG1, FUNC_NAME);
   SCM_ASSERT (scm_is_string (MODE), MODE, SCM_ARG2, FUNC_NAME);
@@ -314,9 +315,9 @@ SCM_DEFINE (scm_mu_mailbox_get_port, "mu-mailbox-get-port", 2, 0, 0,
 		  "Cannot get mailbox stream",
 		  scm_list_1 (MBOX));
   s = scm_to_locale_string (MODE);
-  status = mu_port_make_from_stream (MBOX, stream, scm_mode_bits (s));
+  ret = mu_port_make_from_stream (MBOX, stream, scm_mode_bits (s));
   free (s);
-  return status;
+  return ret;
 }
 #undef FUNC_NAME
 

@@ -47,7 +47,7 @@ mu_scm_message_free (SCM message_smob)
   if (mum->needs_destroy)
     mu_message_destroy (&mum->msg, NULL);
   free (mum);
-  return sizeof (struct mu_message);
+  return 0;
 }
 
 static char *

@@ -121,7 +121,7 @@ mu_port_flush (SCM port)
   
   if (wrsize)
     {
-      if (mu_stream_write (mp->stream, (char*) pt->write_buf,
+      if (mu_stream_write (mp->stream, (const char*)pt->write_buf,
 			   wrsize, mp->offset, &n))
 	return;
       mp->offset += n;
@@ -152,7 +152,7 @@ static scm_sizet
 mu_port_free (SCM port)
 {
   mu_port_close (port);
-  return sizeof (struct mu_port); /*FIXME: approximate */
+  return 0;
 }
 
 static int