Update on freeze status of glibc 2.18?

[Roland McGrath]

> I will assume that you would not be opposed to a configure
> switch that turns elision on or off with the default being
> elision off, but no questionable env vars to tune behaviour.

Probably not, if the code enabled by the configure switch does not
diverge from the API and ABI guarantees we already make and does not
include anything generally ugly that we wouldn't want in the tree at all.