FDE augmentation data

Hi, how do I get FDE augmentation data?

[PATCH] backends: Don't depend on linux/bpf.h to compile bpf disassembler.

We only need a few constants and one structure definition from linux/bpf. Just define those in a local lib/bpf.h file. This makes sure the bpf disassembler is always build and included even when elfutils is build on older GNU/Linux systems (and even on other platforms). Signed-off-by: Mark Wielaar