PATCH: Check GLIBC_IFUNC to enable/disable ifunc features

[Siddhesh Poyarekar]

On Thu, Jun 30, 2016 at 06:42:30AM -0700, H.J. Lu wrote:
> comma-separator is fine.  But we need to both turn it on and off.

How about this:

empty string == all disabled
special keyword 'all' == all enabled
comma-separated list == those enabled and rest disabled.

> Also do we need _X86? GLIBC_IFUNC is processor specific.  Why
> pollute environment with
> 
> GLIBC_IFUNC_ARM
> GLIBC_IFUNC_X86

Fair enough.

Siddhesh