We need all the listed packages so upgrade the dependency appropriately.

_exit() calls skip at-exit hooks, which also skips a call to
__gcov_dump() when collecting coverage with gcov, resulting in
inaccurate coverage reports. To mitigate this, define a custom _exit()
function which injects __gcov_dump() just before _exit(), and use a
macro to override the already existing _exit() function.

To make this work without a bunch of includes scattered across the
codebase, inject the coverage-specific include into the compiler command
line when -Db_coverage=true is used.

Let's introduce a test that runs dbus-broker under Address Sanitizer and
Undefined Behavior Sanitizer, while running other tests against it.

The setup to achieve this is slightly convoluted, since we need to run
(and restart) sanitized dbus-broker without nuking the host machine. For
that we setup an nspawn-container that re-uses host's rootfs (to some
degree) and overlays our additions on top of that. This way we can test
(not-only) the full user-space boot with sanitized dbus-broker without
risking "damage" to the host machine.