PATCH: Check GLIBC_IFUNC to enable/disable ifunc features

[Siddhesh Poyarekar]

On Thu, Jun 30, 2016 at 03:39:23PM +0100, Szabolcs Nagy wrote:
> since it is for glibc devs only is it expected to be
> stable across glibc versions?
> 
> may be the env var name could reflect that it is not
> a public api.

Maybe this is a use case for a GLIBC_PRIVATE namespace?  In any case,
if this is going to be part of tunables, there's no ABI/API guarantee
associated with it.  That is, tunables in version may not be present
in another.

Siddhesh