Build warnings libxfce4mcs, xfce4-mixer, xfwm4, xfce4-panel and xfce4-session

[Benedikt Meurer]

Olivier Fourdan wrote:
>>>Here are a couple of fixes for various build warnings in the latest
>>>trunk. (I'm not going to open bug reports for each of them, that's why
>>>I'm using the mailing list).
>>>I know they are all harmless, but he we were making Xfce 4.4 the best
>>>Xfce release ever :-).
> 
> Done for xfwm4 and libxfce4mcs. I'll let benny, jasper and
> danny review and apply the others patches in their respective modules :)

Committed for xfce4-session with revision 22459.

> Thanks,
>    - Olivier

Benedit