Add newfstatat() syscall to seccomp filter allow list.
Add newfstatat() syscall to seccomp filter allow list.

Seemingly newer versions of glibc call newfstatat(), wrapping
fstatat() and breaking kutil_openlog().

According to `man 2 newfstatat`[0] the employed system call might be
called fstatat64() on some systems, meaning this patch might not fix
all Linux systems.

[0] https://man.archlinux.org/man/newfstatat.2.en

kristapsdz/kcgi,kristapsdz/kcgi