diff -up Crypt-RSA-1.99/Makefile.PL.orig Crypt-RSA-1.99/Makefile.PL
--- Crypt-RSA-1.99/Makefile.PL.orig 2017-05-16 13:20:52.773050882 +0200
+++ Crypt-RSA-1.99/Makefile.PL 2017-05-16 13:21:15.934954366 +0200
@@ -8,6 +8,7 @@
##
## $Id: Makefile.PL,v 1.12 2001/05/30 13:10:32 vipul Exp $
+BEGIN { push @INC, '.'; }
use inc::Module::Install;
name 'Crypt-RSA';