diff --git a/mes/module/mes/guile.mes b/mes/module/mes/guile.mes
index f23d2c90..5d960bc6 100644
--- a/mes/module/mes/guile.mes
+++ b/mes/module/mes/guile.mes
@@ -153,3 +153,5 @@
 
 (define (file-exists? o)
   (access? o R_OK))
+
+(define (set-port-encoding! port encoding) #t)