--- XTEA_PP.orig.pm	2015-04-13 15:09:56.000000000 +0200
+++ XTEA_PP.pm	2016-03-04 10:20:15.487604900 +0100
@@ -30,10 +30,10 @@
 my $ELEMENTS_IN_BLOCK = $BLOCK_SIZE / 4;
 
 
-use constant keysize => $KEY_SIZE;
+sub keysize { $KEY_SIZE }
 
 
-use constant blocksize => $BLOCK_SIZE;
+sub blocksize { $BLOCK_SIZE }
 
 
 sub new {