no92
Needs a test and a rebase.
The ABI check is complaining about a removed internal union member, this is not an ABI break though.
Should be ready for review now.
Addressed in part by #1531.
Given that it is also supported on Linux, I am not sure that moving it is the best play - maybe we should enable it if `__MLIBC_LINUX_OPTION || __MLIBC_BSD_OPTION`?
While our policy is (understandibly) to keep futex requirements simple, I don't see how we can avoid requiring support for this; implementing `cnd_signal` (vs `cnd_broadcast`) would profit from this, and...
Implementation-wise I fail to see how passing a count is more complex than a `wake_all` value, while providing a count makes some cases (barriers come to mind, for instance) more...