- Update to 4.23:
* docs/userguide: add an example for negative lookaheads
* docs/userguide: fix default binding mistake
* docs/userguide: add link to tiling drag
* docs/hacking-howto: update build instructions, startup
* docs/debugging: add note about ptrace
* man/i3: remove outdated I3SOCK description
* all: build with -D_FORTIFY_SOURCE=3
* i3bar: fix configuring bars on “output nonprimary”
* i3bar: implement workspace button protocol
* add “focus workspace” command
* allow switching workspaces when in global fullscreen mode
* exec: single-fork instead of double-forking
* share X11 graphics context (GC) globally
* fix regression with i3bar's output nonprimary
* fix top border resizing on tiling windows
* fix workspace not being focused on title bar scroll
* fix mouse bindings in modes
* fix crashes when using machine criterion
* fix for_window not working with urgency flags
* motif hints: respect maximum border style in append_layout