compiler standards (and/or min gcc version) supported with installed headers ?

[Carlos O'Donell]

On 01/02/2013 10:17 AM, Joseph S. Myers wrote:
> On Wed, 2 Jan 2013, Carlos O'Donell wrote:
> 
>> I say we agree that 2.95.3 is the oldest compiler we will support
>> for compiling userspace applications using glibc headers.
> 
> Given that the headers are generally meant to support non-GCC compilers, I 
> think all you might gain is elimination of cases specifically for older 
> GCC, so that older GCC uses the same cases as non-GCC.  Simply changing 
> __GNUC_PREREQ (2, 95) to __GNUC__ is hardly a gain.  (And where the 
> older-GCC case is simply an optimization, or where the older-GCC and 
> non-GCC cases have similar functionality that's not fully conforming, I 
> think a more recent baseline such as 4.1 would be reasonable.)
 
Why choose 4.1 in particular?

Andreas also seems to suggest a newer baseline would be better.

I'm not against it, I'm just not sure I understand why we want one
choice over another.

In a perfect world we support all versions of gcc going back in time
using our infinite resources to accomplish such a task.

In reality we choose a cut-off that is based on some criteria.

What criteria are we using to select the cut-off?

Cheers,
Carlos.