[PATCH] Correct __GNUC_PREREQ for __const__ and __noreturn__ attributes.

[Joseph Myers]

On Tue, 21 Mar 2017, Paul Eggert wrote:

> For what it's worth, Gnulib code uses __attribute__ ((__noreturn__)) for GCC
> 2.8 and later, and  __attribute__ ((__const__)) for GCC 2.95 and later. I
> vaguely recall problems using these attributes in earlier GCC versions, though
> I'm afraid I don't remember the details. Perhaps Glibc wouldn't run into the
> problems, whatever they were.

I think the 2.8 conditional may be in order to support it at the start of 
a function declaration (before the return type), i.e. compatibly with 
_Noreturn.

-- 
Joseph S. Myers
joseph@codesourcery.com