Speed boost with seccomp-bpf

[JeremyRand]

Using seccomp-bpf should give us a noticeable performance boost, by not forcing the tracer to intercept syscalls that we don't care about. Some links:

• https://pchaigno.github.io/strace/2019/10/02/introducing-strace-seccomp-bpf.html
• https://www.kernel.org/doc/html/latest/userspace-api/seccomp_filter.html
• https://www.alfonsobeato.net/c/filter-and-modify-system-calls-with-seccomp-and-ptrace/
• https://stackoverflow.com/questions/55006186/how-to-get-the-return-code-of-the-syscall-using-seccomp-ret-data-and-ptrace-gete