[minicoredumper] Handling of unavailable bytes in minicoredumps by GDB

[John Ogness]

On 2016-07-06, Simon Marchi <simon.marchi at ericsson.com> wrote:
> Since it requires a version of libelf greater than a certain version,
> it would be good to add a version check with pkg-config in
> configure.ac.  Actually, it would be good to have that check anyway.

I had thought about this. But actually, the new version is only required
for this new feature (dumplist section). The minimal core files work
otherwise fine without it. For that reason I decided to have
minicoredumper log a runtime warning, but enforce no buildtime
requirements.

John Ogness