This doesn't really matter, since these are not executed directly, but it's more consistent with everything else and modern systems.
Following advice from maintainers@gnu.org, bring Stow in line with other GNU projects by upgrading it from GPL v2 to v3 https://www.gnu.org/prep/maintain/html_node/Licensing-of-GNU-Packages.html#Licensing-of-GNU-Packages as obtained in plain text and texinfo formats from https://www.gnu.org/licenses/ and adding appropriate headers: https://www.gnu.org/prep/maintain/html_node/License-Notices-for-Code.html#License-Notices-for-Code Fixes #44: https://github.com/aspiers/stow/issues/44
Also add a unit test for this. Fixes #34: https://github.com/aspiers/stow/issues/34
Unlike the other tests, this actually treats stow(1) as a black box script, running it directly rather than require-ing it as a library. This allows us to check things like the exit codes returned.