To be pushed upstream.
Co-authored-by: Julien Muchembled <jm@nexedi.com>

No need to push upstream. We'll drop this patch as soon as re6stnet can
ensure that there is no old babeld in the network.

To be pushed upstream.

This is a MUST according to the Babel Extension Mechanism draft
(Section 2.2.3).

This reverts commit bf8555b2.

This is consistent with Baptiste's work, and is better in any case.

Makes it consistent with the other interface flags.

Without this, later interface definitions override earlier ones
even when they don't specify a value.

Fixes compilation for MIPS.

Conflicts:
	CHANGES