* Add missing modules (fixes warnings and errors).
* Step 1 to unbreak starting Xvfb by making xpra invoke it with
valid log dir ($HOME/.xpra). Without this fix, it is invoked with
~/.xpra, which Xvfb doesn't know how to interpret and uses it
literally (fail). Step 2 will be fixing an Xvfb permission issue:
"xf86OpenConsole: Cannot open virtual console 1 (Permission denied)".
* Use XPRA_INSTALL_PREFIX to make it find its icons.
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