Re: Require GCC 5 or later to build glibc (bug 23993)

[Adhemerval Zanella <adhemerval dot zanella at linaro dot org>]

On 18/12/2018 20:40, Joseph Myers wrote:
> On Tue, 18 Dec 2018, Adhemerval Zanella wrote:
> 
>> Wouldn't be better to focus on change toolchain requirements at the start
>> of release cycle?
> 
> This particular patch is recognizing a requirement that has already been 
> introduced (two months ago - it evidently took a long time for it to be 
> noticed) as a side effect of using atomic_load_relaxed on a pointer to 
> const (I think - in turn, via how the default atomic_load_relaxed 
> constructs an asm output using typeof, resulting in that asm output 
> variable being const and the error quoted in the bug report).  Given that 
> we have such a requirement in fact on some architectures, and given how 
> long we've had 4.9 as official minimum GCC version for building glibc, it 
> seemed to make more sense to make the requirement for GCC 5 an official 
> one everywhere rather than trying to figure out how to get things working 
> on older compilers.
> 

It indeed seems reasonable to change the minimum requirement for 2.28, even
more because the breakage [1] seems to affect most of the architectures. My
point is more for future changes, where I think setting the expectations
on start of release cycle might help users planning on toolchain
upgrade requirements. 

[1] https://gitlab.com/kubu93/toolchains-builder/pipelines/40259702