Getting Zygo/bees btrfs deduplication working on Ubuntu 14.04

Ubuntu 14.04 bees.txt

Getting bees working on Ubuntu 14.04. 

Simply adding g++-4.9 still yields unsatisfied btrfs dependencies, so you'll have to build btrfs yourself too. 
Building bees in docker on 16.04 yields unsatisfied GLIBCXX_3.4.20 and GLIBCXX_3.4.21 bindings on 14.04. I am 
doubtful that bees will run in docker via a bind mount. So far looks like you need to rebuild / use a newer 
btrfs too, that's the next step. The story so far:

cd /usr/src
git clone https://github.com/Zygo/bees.git --depth 1
docker run -ti -v /usr/src/bees:/usr/src/bees ubuntu:14.04

apt update &&
apt -y install software-properties-common &&
add-apt-repository ppa:ubuntu-toolchain-r/test &&
apt update && \
apt -y install g++-4.9 build-essential btrfs-tools uuid-dev markdown git

cd /usr/src/bees

# OR update-alternatives --install /usr/bin/gcc gcc /usr/bin/gcc-4.9 50
CXX=/usr/bin/g++-4.9 make
make

Breaks at:
extentwalker.cc: In member function 'virtual crucible::ExtentWalker::Vec crucible::BtrfsExtentWalker::get_extent_map(off_t)':
extentwalker.cc:515:82: error: no matching function for call to 'call_btrfs_get(u8 (&)(btrfs_file_extent_item*), std::vector<char>&)'
    auto compressed = call_btrfs_get(btrfs_stack_file_extent_compression, i.m_data);
                                                                                  ^