Meson 0.56.2 and Python39 --> dav1d failing

[Ken Cunningham]

> 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.

K