Some people use development versions of glib ...
Merge branch 'po/lr-import'

* po/lr-import:
  Add support for splittoning Lr import.
  Move splittoning definitions to header file.
  Add support for exposure Lr import.
  Rename exposure to blacks.
  Add support for colorzones Lr import.
  Move colorzones definitions to header file.
  Add support for tonecurve Lr import.
  Move static declarations into C part.
Drop usage of DBus-GLib and always enable kwallet
Bump required version of glib to 2.28

We used the api from 2.28 already, so this shouldn't break anything,
just make it clear why a compile might fail later on.
Cleanup last commit

We were still including some header
update darktable-9999.ebuild according to changes in kwallet pwbackend
Better adjustment for hue colorzones Lr import.
Better adjustment for lightness colorzones Lr import.
Added a missing space character in a user-visible message
Fix two uninitialized variables in dt core and monochrome.
Thanks to Daniel Blueman! This fixes #9189
Merge branch 'master' of github.com:darktable-org/darktable
Move bilat definitions to header file.
Add support for clarity/bilat Lr import.
Minor style fix.
WIP