v2-haddock doesn't define __HADDOCK__

[phadej]

Defining it will mean rebuilding stuff. But this is regression, AFAICS.

[gbaz]

is there an example of where this goes wrong?

[ulysses4ever]

A macro like this has since been implemented and removed precisely due to excessive recompilation: #9177

I'm closing this in favor of (better-articulated) #10818