libelf and libdwarf imports

[Bernd Ernesti <veego%NetBSD.org@localhost>]

Hi,

the import of these two libraries where a little sudden and didn't
mention if core knew about it before, which was my understanding
should be done to avoid a long discussion afterwards.

In the past it was common to get some feedback on a mailing list
before doing an import of a new component.

Bernd

P.S. the libelf part may have been mentioned before, but that was
not so recent and imho didn't mentioned how it would been done.