* From FreeBSD via jbeich@, cf * https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=246363 * backports https://hg.mozilla.org/mozilla-central/rev/463069687b3d from https://bugzilla.mozilla.org/show_bug.cgi?id=1624128 ratchov@ confirms that the issue was also present in -esr, and that backporting this commit fixes it - many thanks !