msgpack/msgpack-perl — pull request #15 by rurban (2013-07-17 15:14:04+00:00)
Title: RT#86999 Fix blead dualvar regression

Since 5.19 it is pretty hard to create a PVNV dualvar in PP. Perl does not pollute a NV with a PV slot anymore
via do { my $x=3.0;my $y = "$x";$x }.
Improve the test to use explicit Scalar::Util::dualvar