Dunst does not neccessarily need systemd. Dunst gets started primarily
via DBus. The systemd service is useful on systemd init based systems,
but won't have any impact on non-systemd systems.
To make systemd a soft dependency is neccessary, as pkg-config now also
queries the systemd.pc file, which won't exist on non systemd systems.
As per discussion in #334 drop dependency on gtk3 and instead depend
only on gdk-pixbuf2 for icon loading.
The only gtk3 function used was gdk_cairo_set_source_pixbuf in order to
convert the loaded pixbufs into cairo surfaces for us to render. In
order to drop the dependency this step was bypassed by using pixbufs
export to png capability and importing it into cairo via a pngstream.
There is no need to have a separate VERSION file in release tarballs,
having the version in config.mk directly allows for a proper fallback in
case the git repository and the version file doesn't exists. The most
important example of this is the tarballs that github creates on every
release.
Since after the release a lot of downstream users will not be building
from source, it makes a lot more sense to have an option to fall back to
the Xinerama extension for those that are still on systems that do not
support RandR.
Use a single MULTIMON variable which can be set to either xrandr,
xinerama or none and replace the previous system which used 2 variables
for each extension which were then added to CFLAGS and instead append
xrandr or xinerama respectively to pkg_config_packs so their
availability can be checked with pkg-config.
The main advantage of this is that the extension can now be set from
the command like like so 'MULTIMON=xinerama make'
If Xft.dpi value is not available, auto-detect value based on monitor using randr provided sizes.
Disable Xinerama and enable randr by default.
Also update dpi everytime the monitor changes.
Remove xext and xft as a dependency since they are not currently used
and probably haven't been used a while.
Also remove freetype2 from the pkg-config list, while it is required by
pangocairo it should be included from the pkg-config --cflags call.
