Meson 0.56.2 and Python39 --> dav1d failing

[Craig Treleaven]

> On Feb 6, 2021, at 4:47 AM, Ryan Schmidt <ryandesign at macports.org> wrote:
> 
> 
> 
> On Feb 6, 2021, at 02:14, Ken Cunningham wrote:
> 
>> On Feb 5, 2021, at 10:04 PM, Ryan Schmidt <ryandesign at macports.org> wrote:
>> 
>>> That sounds like what Craig is saying: that meson is now adding a compiler flag that old compilers don't understand. Meson should check whether a compiler supports a flag before it adds it. We should not be responsible for fixing this; the developers of meson should.
>> 
>> I haven’t tested it all to see for myself, but if someone knows for sure it so, then yeah.
>> 
>> Personally I would be happy to hotpatch it rather than have Every Single Meson Build on 10.7 through 10.9 fail until the patch makes it out the door to us in a released version.
> 
> Absolutely, if we can figure out a patch, we patch it. Just saying this is a bug in meson. It's not our responsibility or desire to forever maintain a local patch to fix it.
> 

I reported the issue upstream:

https://github.com/mesonbuild/meson/issues/8307

Craig