Comment 3 for bug 1871129

Commit to blame in glibc:

commit 3537ecb49cf7177274607004c562d6f9ecc99474
Author: Adhemerval Zanella <email address hidden>
Date: Tue Nov 5 21:37:44 2019 +0000

    Refactor nanosleep in terms of clock_nanosleep

    The generic version is straightforward. For Hurd, its nanosleep
    implementation is moved to clock_nanosleep with adjustments from
    generic unix implementation.

    The generic clock_nanosleep unix version is also removed since
    it calls nanosleep.

    Checked on x86_64-linux-gnu and powerpc64le-linux-gnu.

    Reviewed-by: Florian Weimer <email address hidden>

diff --git a/posix/nanosleep.c b/posix/nanosleep.c
index d8564c7119..ed41c8cce7 100644
--- a/posix/nanosleep.c
+++ b/posix/nanosleep.c
@@ -24,10 +24,13 @@ int
 __nanosleep (const struct timespec *requested_time,
             struct timespec *remaining)
 {
- __set_errno (ENOSYS);
- return -1;
+ int ret = __clock_nanosleep (CLOCK_REALTIME, 0, requested_time, remaining);
+ if (ret != 0)
+ {
+ __set_errno (ret);
+ return -1;
+ }
+ return 0;
 }
-stub_warning (nanosleep)
-
-hidden_def (__nanosleep)
+libc_hidden_def (__nanosleep)
 weak_alias (__nanosleep, nanosleep)