test_instag.c depends on PATH_MAX, undefined on the Hurd
Build log: https://buildd.debian.org/status/fetch.php?pkg=libotr&arch=hurd-i386&ver=4.1.0-5&stamp=1452791784
This prevents us from running the test suite on Debian Hurd. No big deal, but sometimes running upstream test suites on non-Linux exposes other, more interesting bugs :)
(from redmine: created on 2016-01-14)