Running os-test on glibc's POSIX headers

[Jonas 'Sortie' Termansen]

Hi glibc,

You might be interested in the os-test project I've been building
lately to test POSIX header comformance. The new include test suite
checks whether the standard library headers declare everything that
POSIX.1-2024 requires, sliced by each option group:

https://sortix.org/os-test/include/ has the raw data
https://sortix.org/blog/os-testing-posix-headers/ is a write-up about
the results

Overall the glibc results are really good and gets a top three spot.
I only tested on my system glibc rather than the latest bleeding
version, but with a bit of feature macro adjustments for
POSIX.1-2024, then the score can rise to a near perfect 95%. There
are some missing declarations, some of which are new POSIX.1-2024
features, some of which might not be added in the Linux kernel.

If you're interested using this project to improve interoperability,
then please dive into the data and have a look :)

This os-test work has been funded by the NLnet foundation and next
up I'll be working on namespace pollution and seeing if functions
actually work if invoked.

Jonas