[vala] (7 commits) Non-fast-forward update to branch wip/depfile

[Rico Tzschichholz <ricotz src gnome org>]

The branch 'wip/depfile' 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:

  76a03d0... compiler: Add "--depfile" option writing package dependenci

Commits added to the branch:

  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 (*)
  18c2e40... compiler: Add "--depfile" option writing package dependenci

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