[PATCH x86_64][BZ #20139] Don't allow configure with not supporting AVX512 assembler w/o --disable-avx512.

[Joseph Myers]

On Mon, 27 Jun 2016, Andrew Senkevich wrote:

> Hi,
> 
> this patch adds new configure option --enable-avx512 and defaults it for 
> x86_64.
> 
> To fix BZ #20139 we need don't let to configure with not supporting
> AVX512 assembler w/o --disable-avx512.

What assembler version is required to support AVX512, and when was that 
version released?  It might be better to increase the minimum binutils 
version for building glibc (generally, or for x86_64).

-- 
Joseph S. Myers
joseph@codesourcery.com