Enhancement: config error reporting about labwc

[stefonarch]

In labwc you can tell to have an issue in rc.xml when window decoration defaults after reload, but you have to find the error in the xml file by yourself.

I remember sway having a similar message on top which indicates the faulty line. So kind of xml syntax checker tool would be needed probably.

[Consolatis]

Labwc does log various config errors but only to stderr. That usually doesn't really help when within the labwc session.

[droc12345]

I knew it output to stderr, but I typically run with logging >/dev/null, unless I have a problem.
That's why it would be nice to have an on screen or popup for errors, while in session.

Anyway, just something to think about, no immediate need for it.

Edit to add: something like a function that would take a string to output would work,
and while parsing the config file, any errors could just call the function as well as the log,

ETA2: If not this then something like "labwc --check-config" or a separate config file checker
that would inform one of any errors.