Flatpak-builder is a tool for building flatpaks from sources.
See http://flatpak.org/ for more information.
Read documentation for the flatpak-builder commandline tools.
Flatpak-builder uses a traditional autoconf-style build mechanism. To build just do
./configure [args]
make
make install
Most configure arguments are documented in ./configure --help. However,
there are some options that are a bit more complicated.
Flatpak-builder relies on flatpak, so it must be installed first.