remove EGL parameter from backend_autocreate

Tracking with breaking change in swaywm/wlroots#2593.

Revert "Allow toggling the layout before selecting a different one"

This reverts commit 90cc3b1e2c824db74e932dbb9733d398619a037c.  Didn't
mean to merge this change.

flesh out cleanup

This is the order of *_destroy calls which resulted in the fewest
errors/leaks detected by Valgrind.  Most of the errors come from the
gbm_allocator code - will have to figure out which destroy call is still
missing.

fix segfault in xwayland cursor manager

macroize event handlers

This was a prime candidate for reducing the verbosity of some of our
code

no need to cast NULL to void *

consolidate some of the ugliness into a separate file

Similar to Linux kernel approach, encapsulate some of the uglier
conditional compilation into inline functions in header files.

The goal is to make dwl.c more attractive to people who embrace the
suckless philosophy - simple, short, hackable, and easy to understand.
We want dwm users to feel comfortable here, not scare them off.  Plus,
if we do this right, the main dwl.c code should require only minimal
changes once XWayland is no longer a necessary evil.

According to `cloc`, this also brings dwl.c down below 2000 lines of
non-blank, non-comment code.

fix build with -DXWAYLAND

don't call applyexclusive just to return

let's not alienate the dwm folks

Fix style.

Merge updates from guidocella

Thanks so much for helping to keep the project running while life was
crazy!

Merge pull request #32 from alex-courtis/24-xwayland-cursor

#24 ensure that xwayland cursor defaults to left_ptr

simplify ROUND macro

Merge pull request #54 from Bonicgamer/swayscalebox

Sway scale_box (rounding)

Merge pull request #53 from Stivvo/fullscreen

Fullscreen support

fix crash on non-libinput pointers (e.g. X11 backend)

Merge pull request #49 from guidocella/layer-shell

Layer shell

Merge pull request #62 from Java-boi/master

Added basic tap-to-click for touchpad users

Merge pull request #66 from richardipsum/master

fix undeclared WLR_KEY_PRESSED

Change fullscreen policies

When a new client is spawned, fullscreen isn't disabled for all clients
in that monitor any more.

Instead, all fullscreen clients are kept fullscreen, while other clients
spawn in the background.

When fullscreen is disabled, all clients are rearranged.

This is made to make dwl more flexible allowing multiple fullscreen
clients at the same time, have floating clients on top of a fullscreen
one and let stuff happen without quitting fullscreen, like many other
WMs and DEs.