[PATCH 1/2] Add __clang_has_extension to sys/cdefs.h.

[Florian Weimer]

On 04/23/2016 01:05 AM, Zack Weinberg wrote:
> 	* misc/sys/cdefs.h: New utility macro __clang_has_extension.

I don't feel strongly about this, but the identifier looks like it's in 
the Clang namespace.  Perhaps use __glibc_clang_has_extension instead?

Florian