Hi, I've successfully built master packages with my patch (forcing HTTP::OAI@3.x dependency)[1]. They also install with no issue in Stretch. Here's what you need to test yourself:

https://cloud.theke.io/s/AyfTWpXt6R87epe

Basically download everything somewhere and:
$ vagrant up
$ vagrant ssh
v$ wget -q -O- https://debian.koha-community.org/koha/gpg.asc | sudo apt-key add -
v$ echo 'deb http://debian.koha-community.org/koha unstable main' | sudo tee /etc/apt/sources.list.d/koha.list
v$ apt update
v$ sudo dpkg -i /vagrant/libhttp-*.deb
v$ sudo apt -f install
v$ sudo dpkg -i /vagrant/koha-deps*.deb
v$ sudo apt -f install
v$ sudo dpkg -i /vagrant/koha-perldeps*.deb
v$ sudo apt -f install
v$ sudo dpkg -i /vagrant/koha-common*.deb
v$ sudo apt -f install

Voila.