From: Daniel Borkmann <redacted>
Date: Mon, 23 Dec 2013 18:54:31 +0100

We could entirely remove it as it was e.g. proposed in 2008 [1]
already if you see any value in that. Eventually it's up to Dave and
if he likes, I'll be happy to send a patch that removes this define.

Removing user visible defines can break source builds, for example
someone building string tables or auto-generating things to facilitate
accessing these values from languages other than C.

It's harmless, since nobody semantically expects anything of it, but
we have to keep it around.