This patch simplifies the propagation of pointer shapes from
window-manager clients to the pointer. The "shape" report is routed to
the wm server, which, in turn, reports it to the pointer. This way, the
pointer can easily correlate the label of the application's "shape"
report with the label of the application's Nitpicker session. The
formerly used manual rewriting of the "shape" label is not needed
anymore.
Since the wm server provides a "Report" service now, its <provides>
declaration must cover "Report" in addition to "Nitpicker" to avoid
runtime error messages. Vice versa, the wm is now expected to request
"shape" reports, which should be routed to the pointer (using the
'label_last' routing attribute).
Fixes#3165
The situation where a 'Session_policy' is constructed for a label with
no matching policy is in almost all cases a configuration problem.
A diagnostic message eases pin-pointing such mistaks. By adding the
message to the 'Session_policy', servers don't need to manually handle
the exception to provide diagnostic information. This simplifies the
server code in many components.
This commit moves the window layouter and window decorator into
dedicated packages that can now be combined with the "wm" server at
runtime and restarted/reconfigured/swapped-out independently.
To use the window manager, one must start the 'wm', 'window_layouter',
and one of the 'motif_decorator' or 'themed_decorator' subsystems.
Fixes#3024
