PATCH: Check GLIBC_IFUNC to enable/disable ifunc features

[Siddhesh Poyarekar]

On Wed, Jun 29, 2016 at 08:22:15PM -0700, H.J. Lu wrote:
> GLIBC_IFUNC must be processed after init_cpu_features is called and before
> any relocation is performed.  Otherwise, IFUNC won't work correctly.  Can your
> tunable scheme support it?

Yes, one of the desired use cases for tunables has been to control
IFUNC behaviour.

Siddhesh