[vala] (15 commits) Non-fast-forward update to branch wip/ci

[Rico Tzschichholz <ricotz src gnome org>]

The branch 'wip/ci' was changed in a way that was not a fast-forward update.
NOTE: This may cause problems for people pulling from the branch. For more information,
please see:

 https://wiki.gnome.org/Git/Help/NonFastForward

Commits removed from the branch:

  d2cfc47... coverage: Build gidl-bindings
  07a96c3... ci: Add .gitlab-ci.yml
  db3cd40... ci: Add ubuntu:16.04 run with gcc
  c754c37... ci: Add ubuntu:18.04 run with gcc
  cd91800... ci: Add fedora:latest run with clang
  0dfb0c6... ci: Add archlinux/base:latest run with gcc
  ad5619f... ci: archlinux/bison - https://bugs.archlinux.org/task/64165
  a18ec60... ci: Always deploy

Commits added to the branch:

  8677f09... vala: Improve error message for unsupported inner types and (*)
  8ee44db... vala: Don't allow "va_list" as return-type or type of field (*)
  7551bbb... codegen: Remove unreachable code in TypeRegisterFunction.in (*)
  6b03920... codegen: Improve *_get_type() fast path (requires glib >= 2 (*)
  804160d... codegen: Don't attribute *_get_type_once() with G_GNUC_CONS (*)
  cf4a50c... glib-2.0: Add to_string() for GLib.PollFd and GLib.Pid (*)
  e0a963f... glib-2.0: Add new symbols from 2.64 (*)
  33f4a23... coverage: Build gidl-bindings
  95c7fcc... ci: Add .gitlab-ci.yml
  8cf4172... ci: Add ubuntu:16.04 run with gcc
  780c211... ci: Add ubuntu:18.04 run with gcc
  4c2a0b7... ci: Add fedora:latest run with clang
  6f2470e... ci: Add archlinux/base:latest run with gcc
  001d3b9... ci: archlinux/bison - https://bugs.archlinux.org/task/64165
  9956543... ci: Always deploy

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