diff -up Image-Math-Constrain-1.02/Makefile.PL.orig Image-Math-Constrain-1.02/Makefile.PL
--- Image-Math-Constrain-1.02/Makefile.PL.orig	2017-05-18 12:22:53.157260054 +0200
+++ Image-Math-Constrain-1.02/Makefile.PL	2017-05-18 12:30:17.112318821 +0200
@@ -1,3 +1,5 @@
+BEGIN { push @INC, '.'; }
+
 use inc::Module::Install 0.76;
 
 all_from      'lib/Image/Math/Constrain.pm';