Import of PERLANCAR/DefHash-1.0.6 from CPAN.

gitpan-cpan-distribution: DefHash
gitpan-cpan-version:      1.0.6
gitpan-cpan-path:         PERLANCAR/DefHash-1.0.6.tar.gz
gitpan-cpan-author:       PERLANCAR
gitpan-cpan-maturity:     released