Move header files in the same folder than Go files

[lebauce]

When using iovisor/gobpf from a project using Go modules, the bpf.h and bpf_map.h files and not imported as they are in the include subdirectory.
This fix makes it possible to use gobpf in a go.mod file.

[lebauce]

@alban Can you please have a look ? Thank you !

[bboreham]

If I understand correctly, this is to resolve the same problem described at golang/go#26366 (comment)

👍 from me.

[alban]

LGTM (after the conflict is resolved)

[mauriciovasquezbernal]

@lebauce could you please solve the conflict?

[lebauce]

@alban @bboreham Seems like I completely missed the notifications on this one. I just rebased my PR. Sorrry for the delay

[lebauce]

@alban Do you think we could remove the "do-not-merge" tag ? Thanks !

[mauriciovasquezbernal]

Hi @lebauce, sorry for the big delay. I believe we can't merge this PR, as described in #234, some of the files we pull from the kernel expect a linux/filename.h structure, if we move everything into the same folder we'll have to modify all those files making it difficult to maintain.

I think we should move ahead and merge #217 then.

[lebauce]

@mauriciovasquezbernal Thanks for your explanation. It perfectly makes sense. Can we then move forward and merge #217 (once the doc.go file is also added to elf/include, elf/include/linux, elf/include/uapi, elf/include/uapi/linux and elf/lib) ?