faccessat(2): Honor AT_SYMLINK_NOFOLLOW

[fernape]

Summary

Make the system call honor AT_SYMLINK_NOFOLLOW.

Also enable this from linux_faccessat2 where the issue arised the first time.
Update manual pages accordingly.

PR: 275295

Test Plan

Apply the patch and use a simple program to test the system call.
One such program can be found here.

AFAICT, this change is POSIX-compliant.

[kib]

Do not forget to bump the man page's dates.

sys/compat/linux/linux_file.c

639

This line should be wrapped.

sys/kern/vfs_syscalls.c

2155

The line should be wrapped. I do not see a need to add {} around the body.

[fernape]

• Address kib's feedback.

[fernape]

In D46267#1055079, @kib wrote:

Do not forget to bump the man page's dates.

Yes, I will bump .Dd at commit time.

[kib]

sys/compat/linux/linux_file.c

640

Indent for the continuation line should be +4 spaces

sys/kern/vfs_syscalls.c

46

Stray chunk

2156

Again, indent should be +4 spaces

[fernape]

• Use +4 spaces for indentation.

[fernape]

• Remove stray change.