Add file descriptor tracking in wrappers for bpf system call

Add file descriptor tracking in wrappers for bpf system call

Support for the bpf system call was added in a previous commit, but
did not include tracking for file descriptors handled by the call.

Add checks and tracking for file descriptors. Check in PRE() wrapper
that all file descriptors (pointing to object such as eBPF programs or
maps, cgroups, or raw tracepoints) used by the system call are valid,
then add tracking in POST() wrapper for newly produced file descriptors.

As the file descriptors are not always processed in the same way by the
bpf call, add to the header file some additional definitions from bpf.h
that are necessary to sort out under what conditions descriptors should
be checked in the PRE() helper.