BLD: update vendored Meson for cross-compilation patches

[rgommers]

Pulls in numpy/meson#16 from our Meson fork for 2.1.0 (xref gh-27044). A full update to Meson 1.5.1 won't make it in in time for 2.1.0, so this is helpful.

Draft PR to test in CI before merging numpy/meson#16

[rgommers]

This is integrating a change conda-forge would like before the 2.1.x branch creation. CI is happy, so I'll go ahead and merge straight away.

[charris]

Does this need a backport?

[rgommers]

To 2.0.x? I didn't consider that yet. Not sure - @h-vetinari?

[h-vetinari]

If there's a chance for a 2.0.2, I think it should be backported. If someone creates a branch at the commit in numpy/meson that's currently in 2.0.x, I can do the same backport there.

[charris]

@h-vetinarivendored-meson/meson is a submodule, nothing special needed.

[h-vetinari]

@h-vetinarivendored-meson/meson is a submodule, nothing special needed.

I get the submodule part, but I had falsely assumed that the vendored meson had already diverged between 2.0.x and main (and in that case it would have been necessary to either point to the same submodule commit as main, or backport the patches to the meson commit that 2.0.x pointed to in that hypothetical scenario)