Prevent CPAN testers from reporting errors on platforms other than MSWin32 and cygwin

Author: jandubois

Makefile.PL

@@ -1,6 +1,10 @@
 use strict;
 use ExtUtils::MakeMaker;
 
+unless ($^O eq "MSWin32" || $^O eq "cygwin") {
+    die "OS unsupported\n";
+}
+
 my @libs;
 push @libs, '-L/lib/w32api -lnetapi32' if $^O eq "cygwin";