lib: posix: nanosleep #25554
Description
Is your enhancement proposal related to a problem? Please describe.
nanosleep(2) is required for std::chrono in C++, among other things. It's POSIX (IEEE 1003.1) as well.
Describe the solution you'd like
I'll create a PR.
Describe alternatives you've considered
Looked into newlib. There is no de-facto implementation of nanosleep. It generally just makes a system call. FWICT, Zephyr only has k_msleep() precision, which relies on ticks, FWICT.
Additional context
Loosely related to #24730 (where reusing time.h header from libc was mentioned)
Required by #25527