[gegl/wip/schumaml/vala-build] (14 commits) ...Merge branch 'wip/schumaml/vala-build' of https://gitlab.gnome.org/GNOME/gegl into wip/schumaml/vala

[Michael Schumacher <schumaml src gnome org>]

Summary of changes:

  28510dc... Update Polish translation (*)
  9fb676a... Extend configure checks with checks for SDL2 (*)
  d0c939f... Port sdl-display to SDL2 (*)
  17f068e... Port sdl-draw example to SDL2 (*)
  7a2621b... tools: exp_combine fix signedness warning (*)
  fd361b3... gitlab-ci: set XDG_DATA_DIRS in environment for gegl build (*)
  4c561bd... gitlab-ci: use master if babl micro is odd (*)
  9d1e254... configure.ac: depend on babl-0.1.71 (*)
  00c2aad... gitlab-ci: do the min-babl checkout in a shell conditional (*)
  34dba25... gitlab-ci: attempt to use $() instead of `` inside arithmet (*)
  84ae94f... gitlab-ci: conditional execution for babl-min-version (*)
  71d8e28... opencl: in gegl_buffer_cl_iterator_next add gegl_buffer_set (*)
  68b9bde... build: add vala to .gitlab-ci.yml to spot any vala-related 
  6415d30... Merge branch 'wip/schumaml/vala-build' of https://gitlab.gn

(*) This commit already existed in another branch; no separate mail sent