Standard scheme for maintainer-only debugging code?

[Nathanael Nerode]

Joseph S. Myers asked:
>Why does this code need to be compiled out?
Speed.  Sometimes (quite often actually) such code is in deeply inner 
loops.  For one reason or another, one instance of such code might 
trigger hundreds of times per compilation.  Combine that with hundreds 
of such instances, and you *want* this out of release versions of the 
compiler.

You really want it to be compiled out *unless* you're doing a special 
maintainer debug build.

--Nathanael