Fix md5-digest-for-port: Don't fail if the total number of bytes read from a port exactly matches the buffer size

scsh/md5.scm

@@ -70,7 +70,9 @@
     (init-md5-context! context)
     (let lp ()
       (let ((got (read-block buffer 0 buffer-size port)))
-	(cond ((< got buffer-size)
+	(cond ((eof-object? got)
+	       (md5-context->md5-digest context))
+	      ((< got buffer-size)
 	       (if (not (eof-object? (peek-char port)))
 		   (error "read-block didn't read port to the end"))
 	       (update-md5-context! context (substring buffer 0 got))