Change some optional dependencies from being optional to being mandatory
or being mandatory but behind on-by-default cmake flags. Eg: instead of
only compiling Wayland support if we find the appropriate libraries, we
always require the libraries unless the user specifies WITH_WAYLAND=OFF.
Optional libraries are hard to discover by packagers (since they don't
see an error once we add them) and create lots of possible build flavors
with a different features that can confuse users.
In theory we support Qt 5.6 (because of SailfishOS) but in practice we are not checking that in the CI so probably we broke the compatibility long ago. Also, I don't think anyone is using this code in SailfishOS, so we can greatly simplify the code by requiring Qt 5.15 or later.
Instead of always doing so on MacOS, do it only when we get a
DatagramTooLargeError. On MacOS, the size is limited only for
broadcast but not for unicast.
This is here because the kdeconnect shortcut launches the
app, not the systray. The app launches the daemon via dbus
but without this, we don't have a systray.
Ideally the systray and daemon would be the same process.
Also ideally we would have a way to launch the daemon and
systray at boot, so people don't have to launch the app
just for the side effect of starting the daemon.
This reverts commit 1dcfaf5108.
Since sockets are buffered `QIODevices` we can use `canReadLine()` to check
if we have a full line, instead of using a custom `SocketLineReader` class
(and the copy-pasted `DeviceLineReader` in the Bluetooth backend).
We can also loop through all the lines instead of queuing calls to `dataReceived`.
And we don't need transactions.
Every time a device is selected, `pluginsConfigChanged` would trigger even
if no plugins actually changed (there's a boolean to distinghish that on
the signal that we were ignoring). On top of that, we were connecting to
the signal again each time we selected a device, causing this bug to
trigger N+1 times every time a device was selected.
This is bad because `pluginsConfigChanged` would reload all the plugins,
which for some plugins even implies network calls to the connected device.
