oktw says to #ysitd
<licson>: Binaries are built with a CentOS 5 base image with help of docker. That ensures that they are built against version of GLIBC that is reasonably old not to cause problems with symbol versioning. All the dependencies are also built inside chroot from latest stable tarballs. They are packed together with PyPy into one distribution and RPATH entries are inserted into them (this ensures that they can be found relatively to each other).