[fprint] Drivers API changes

[Bastien Nocera]

On Tue, 2018-05-29 at 19:57 +0300, Igor Filatov wrote:
> Looks like G_DEBUG_HERE is only available in glib >= 2.50. Might set
> the bar too high. For ex. latest Mint has 2.48 and the oldest Ubuntu
> LTS (14.04) only has 2.40. I think the latter could be a good
> baseline.

GLib 2.50 was released in September 2016. I think that's enough time
for distributions to catch up. LTS distributions can backport glib if
they want the new library.

We're just in the middle of a development cycle anyway, we'll see when
it's deployed.

Cheers