Bug#823451: libbitcoin fails to build on all archs except x86

[Matthias Klose]

Package: src:libbitcoin
Version: 2.11.0-1
Severity: serious
Tags: sid stretch

libbitcoin fails to build on all release archs except x86, where it built 
before.

see https://buildd.debian.org/status/package.php?p=libbitcoin