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.
This is now necessary in order to prevent pause.perl.org from
complaining:
Status: Decreasing version number
=================================
module : Stow::Util
version: undef
in file: lib/Stow/Util.pm
status : Not indexed because lib/Stow/Util.pm in
A/AS/ASPIERS/Stow-v2.2.0.tar.gz has a higher version number
(0)
http://article.gmane.org/gmane.comp.sysutils.automake.general/13192
This means that it is still included in the distribution and
installed, but is only automatically (re)built when making a
new distribution - if stow.texi changes during development, it
has to be rebuilt manually via 'make pdf'.
