[gtk] (53 commits) Created branch 4.0-backports

[Matthias Clasen <matthiasc src gnome org>]

The branch '4.0-backports' was created.

Summary of new commits:

  201580b... Abort if the shared memory pool cannot be created
  3ac71e4... a11y: Avoid signal emission during cache population
  5fb3daf... a11y: Make GtkATContext realization lazier
  2624000... wayland: Explicitly announce ssd for kwin
  73617ee... Avoid a heap-use-after-free
  90ef388... testsuite: Fix a leak
  100de32... Avoid a buffer overrun
  6161168... modules: Simplify _gtk_get_module_path
  295454d... searchbar: Fix documentation mishap
  c225959... docs: Update border-size docs
  949fb8a... gtkgstsink: Report allocation size even if no pool requeste
  c2235ce... gtkgstsink: Use video_frame_free also for the GL path
  2194421... widget: Fix can-focus
  b85296b... docs: Add gtk_widget_grab_default to migration guide
  0240db0... builder-tool: Translate GtkImage:pixbuf
  9863528... Drop unused logo resource
  e43376c... Remove vestigial glade support
  08b1d2b... wayland: Signal gtk-shell surface destruction to the server
  13724b6... node editor: Make help textview monospace
  3a9c035... shader builder: Improve error output
  f5bb580... docs: Remove stray code block end marker
  4e6d62f... docs: Use the appropriate syntax for code block language
  91549c2... docs: Escape bare tags
  a2253ff... docs: Annotate XML fragments as such
  f992308... build: Disable subproject Cairo tests
  5f1a474... gtkgstsink: Sync texture before handing it to GDK
  3990cd2... tests: Disable the textview-margins reftest
  22fc7b3... nativedialog: Add more docs
  0e2863a... Remove a forgotten file
  f218190... gdk/toplevelsize: Remove warnings about exceeding bounds
  7498e3b... css: Allow transitioning different-size shadows
  05cfd09... x11: Handle X-specific targets in drops
  4cd4d75... Adwaita: allow suggested and destructive action buttons in 
  7af9d1f... css: Fix shadow value equal
  e99fa00... docs: Mention css drop-shadow filter
  d3d0324... vulkan: Fix image uploading by regions
  bcd4068... css: Fix border value parsing
  047c8f7... listbase: Don't specify the same thing twice
  85b98cb... textbtree: Avoid line vs char count confusion
  647bc9f... x11: A case of argument order confusion
  44cb05c... messagedialog: Don't initialize twice
  acb3e48... gdk: Remove a redundant check
  7f9d89e... a11y: Avoid out-of-bounds access
  284dd6a... css: Drop a bit of unreachable code
  8099c46... treemodelfilter: Drop unreachable code
  d43a6c0... docs: Rewrite the long description for GtkDialog
  af1d187... gtkshow: Fix doc typo
  d1695ed... iconbrowser: Make image dnd work again
  cc55d66... meson: use correct module file extension on macOS
  26b0554... x11: Some code cleanups
  7e9f081... x11: Fix a memory leak
  384f268... x11: Pass mimetypes when creating output stream
  0b75188... x11: More dnd fixes