@jschauma two ways to suggest that others add it:
1) mail the https://www.openwall.com/lists/libc-coord/ mailing list - many libc maintainers are found here. for a variety of Linux & Unix libc implementations.
2) suggest it to the Austin Group for a future POSIX version - either via email or bug report (see https://www.opengroup.org/austin/ ) - though they may want to see some evidence that software is actually calling it first, and I don't see any that does yet.