Microsoft Windows imposes strict filename restrictions on its platform.
As RDP is developed by Microsoft and the RDS in MS Windows is typically
used as remote desktop server for the RDP protocol, these filename
restrictions are also enforced in WinPR, when copy-pasting files over
the clipboard.
However, in some connections no peer on MS Windows is involved and in
these situations, these filename restrictions are just an annoyance.
With a recent API addition in WinPR, it is now possible to override the
callback, where the filename is checked, whether it is valid.
So, use this new API to relieve the filename restriction, when the
connected remote desktop server is not on MS Windows.
The X11 core protocol does not have support for selection ownership
notifications. Until now xfreerdp worked around this issue by always sending
a format list pdu to the server after sending the format data response pdu
which makes the server side think that the clients clipboard data has changed.
This workaround has some severe drawbacks:
* it causes unnecessary data transfers because even without local clipboard
data changes the same data is always re-transferred over the channel
* with some clipboard managers (in the server sessions) you will get massive
endless data transfer loops because these managers immediately request the
data on clipboard changes.
The correct (core X11) way would be polling for selection ownership changes
which must include the ability to detect changes to the TIMESTAMP target if
the selection owner did not change.
The alternative to the poll based approach is using the X Fixes extension in
order to get selection ownership notifications.
This commit adds support for the XFIXES solution and also moves the complete
clipboard related event handling from xf_event.c to xf_cliprdr.c
