Explain of problem: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=198758#c18
*** This bug has been marked as a duplicate of bug 202599 ***
Avoid problem != fix problem: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=207723
New upstream version has been committed in r410448 (head) and 410471 (2016Q1).