fork on macOS 10.14.6 shows leaks

[GroteGnoom]

For this file

#include<unistd.h>
int     main()
{
        fork();
}

if I run

clang test_fork.c -fsanitize=leak && ./a.out

I get leaks:

=================================================================
==12452==ERROR: LeakSanitizer: detected memory leaks

Direct leak of 16 byte(s) in 1 object(s) allocated from:
    #0 0x104f56988 in wrap_malloc+0x58 (libclang_rt.lsan_osx_dynamic.dylib:x86_64+0x8988)
    #1 0x7fff7885fb17  (libsystem_notify.dylib:x86_64+0x3b17)
    #2 0x7fff7885faf6  (libsystem_notify.dylib:x86_64+0x3af6)
    #3 0x7fff78865aaa in _os_once_callout+0x11 (libsystem_platform.dylib:x86_64+0x1aaa)
    #4 0x7fff78865a6e in _os_alloc_once+0x29 (libsystem_platform.dylib:x86_64+0x1a6e)
    #5 0x7fff78860d29 in _notify_fork_child+0xd2 (libsystem_notify.dylib:x86_64+0x4d29)
    #6 0x7fff75662b12 in libSystem_atfork_child+0x30 (libSystem.B.dylib:x86_64+0x1b12)
    #7 0x7fff786d6d96 in fork+0x27 (libsystem_c.dylib:x86_64+0xfd96)
    #8 0x104f45f88 in main+0x8 (a.out:x86_64+0x100000f88)
    #9 0x7fff7867d3d4 in start+0x0 (libdyld.dylib:x86_64+0x163d4)

Direct leak of 16 byte(s) in 1 object(s) allocated from:
    #0 0x104f56988 in wrap_malloc+0x58 (libclang_rt.lsan_osx_dynamic.dylib:x86_64+0x8988)
    #1 0x7fff7885fb17  (libsystem_notify.dylib:x86_64+0x3b17)
    #2 0x7fff7885fae8  (libsystem_notify.dylib:x86_64+0x3ae8)
    #3 0x7fff78865aaa in _os_once_callout+0x11 (libsystem_platform.dylib:x86_64+0x1aaa)
    #4 0x7fff78865a6e in _os_alloc_once+0x29 (libsystem_platform.dylib:x86_64+0x1a6e)
    #5 0x7fff78860d29 in _notify_fork_child+0xd2 (libsystem_notify.dylib:x86_64+0x4d29)
    #6 0x7fff75662b12 in libSystem_atfork_child+0x30 (libSystem.B.dylib:x86_64+0x1b12)
    #7 0x7fff786d6d96 in fork+0x27 (libsystem_c.dylib:x86_64+0xfd96)
    #8 0x104f45f88 in main+0x8 (a.out:x86_64+0x100000f88)
    #9 0x7fff7867d3d4 in start+0x0 (libdyld.dylib:x86_64+0x163d4)

Indirect leak of 2048 byte(s) in 1 object(s) allocated from:
    #0 0x104f56bcd in wrap_calloc+0x5d (libclang_rt.lsan_osx_dynamic.dylib:x86_64+0x8bcd)
    #1 0x7fff7885fb3e  (libsystem_notify.dylib:x86_64+0x3b3e)
    #2 0x7fff7885faf6  (libsystem_notify.dylib:x86_64+0x3af6)
    #3 0x7fff78865aaa in _os_once_callout+0x11 (libsystem_platform.dylib:x86_64+0x1aaa)
    #4 0x7fff78865a6e in _os_alloc_once+0x29 (libsystem_platform.dylib:x86_64+0x1a6e)
    #5 0x7fff78860d29 in _notify_fork_child+0xd2 (libsystem_notify.dylib:x86_64+0x4d29)
    #6 0x7fff75662b12 in libSystem_atfork_child+0x30 (libSystem.B.dylib:x86_64+0x1b12)
    #7 0x7fff786d6d96 in fork+0x27 (libsystem_c.dylib:x86_64+0xfd96)
    #8 0x104f45f88 in main+0x8 (a.out:x86_64+0x100000f88)
    #9 0x7fff7867d3d4 in start+0x0 (libdyld.dylib:x86_64+0x163d4)

Indirect leak of 2048 byte(s) in 1 object(s) allocated from:
    #0 0x104f56bcd in wrap_calloc+0x5d (libclang_rt.lsan_osx_dynamic.dylib:x86_64+0x8bcd)
    #1 0x7fff7885fb3e  (libsystem_notify.dylib:x86_64+0x3b3e)
    #2 0x7fff7885fae8  (libsystem_notify.dylib:x86_64+0x3ae8)
    #3 0x7fff78865aaa in _os_once_callout+0x11 (libsystem_platform.dylib:x86_64+0x1aaa)
    #4 0x7fff78865a6e in _os_alloc_once+0x29 (libsystem_platform.dylib:x86_64+0x1a6e)
    #5 0x7fff78860d29 in _notify_fork_child+0xd2 (libsystem_notify.dylib:x86_64+0x4d29)
    #6 0x7fff75662b12 in libSystem_atfork_child+0x30 (libSystem.B.dylib:x86_64+0x1b12)
    #7 0x7fff786d6d96 in fork+0x27 (libsystem_c.dylib:x86_64+0xfd96)
    #8 0x104f45f88 in main+0x8 (a.out:x86_64+0x100000f88)
    #9 0x7fff7867d3d4 in start+0x0 (libdyld.dylib:x86_64+0x163d4)

SUMMARY: LeakSanitizer: 4128 byte(s) leaked in 4 allocation(s).

And I'd expect there to be no leaks at all.

This is on macOS 10.14.6, with Homebrew clang version 13.0.0