Prevents needlessly launching the saver at startup when launched by xss-lock and the screen is already blanked.

Related to issue #84.

This isn't quite what I want, so for now it's already marked deprecated.
Only there for testing a solution to issue #95.

The leak does not actually have any impact as it only occurs in the error case
in which the calling process (auth_x11) exits anyway; yet fixing this
anyway seems a good idea.

cat_authproto (the demo program) had an actual, real leak with this,
even - but it is a test program only.

Also remove a potential bad pointer dereference in case NULL isn't the
zero bit pattern.

Fixes #96.

It documents where the xbm file comes from.

Fixes #90.

Now it compiles as C89 again.

Fixes #85.

That way, when a user ever sees it, they see the cause of the problem:

INCOMPATIBLE COMPOSITOR,
PLEASE FIX!

Then we can safely show Ctrl+Alt+O on the screen :)

At least one user tried to press zero instead of oh; changed Ctrl-Alt-O
(upper case) to Ctrl-Alt-o (lower case) to disambiguate.

Should fix crash issues with nvidia driver.

Credit goes to tommie.

This doesn't make them work, we still need to switch to another font
renderer, but this fixes the crash of auth_x11 when using them.

See bug #83.

This already closes lots of context menus and makes the force grab code hit less.

Makes sure our and X11's idle timers are more consistent. Should normally
only have had a delta of below 100ms though (WATCH_CHILDREN_HZ is 10,
and XPending flushes).

Fixes "xsecurelock while slock is running may unmap all your windows".

No behavioral change.

That way, helpers can still expect to live in that directory.

INTERNAL_REFERENCE=140864646

Fixes "xsecurelock gets into non-unlockable state if Debian package is reinstalled/upgraded while the screen was locked".

INTERNAL_REFERENCE=140864646

Also, provide a general variable
(XSECURELOCK_ALLOW_LOCKING_IF_INEFFECTIVE) to bypass these checks,
when wanting to develop XSecureLock itself on a Chromebook (Wayland!) for
example.

Works around issues in third-party authentication modules.

Fixes #39.

Fixes #81.

This shouldn't be necessary but may work around graphics driver bugs.

Fixes #80.