This contains significant rebase / merge / testing work by Naut
<lbrynaut@protonmail.com>, Anthony Fieroni <bvbfan@abv.bg> and Brannon
King <countprimes@gmail.com>.
Descriptors now make use of the dependencies builder, so results are cached.
A very new version (>= e9741525c) of Gitian should be used in order to take
advantage of caching.
We're not ready to switch to a static qt5 for Linux yet due to missing plugin
support. This adds a recipe for building a shared qt4 that we build and link
against, but don't distribute.
make USE_LINUX_STATIC_QT5=1 can be used to build static qt5 as before.
