Makefile.PL relied on the fact that current directory is in @INC. Fix is to
force to read the configuration from current directory instead.

Upstream fix: https://anonscm.debian.org/viewvc/net-ssleay?view=revision&revision=489

--- Net-SSLeay-1.78/Makefile.PL	2017-04-05 10:42:56.999409375 +0000
+++ Net-SSLeay-1.78/Makefile.PL	2017-04-05 10:40:21.465210478 +0000
@@ -3,6 +3,7 @@
 use strict;
 use warnings;
 use lib 'ext';
+use lib '.';
 use inc::Module::Install;
 use Config;
 use File::Spec;