clients: configure cursor theme from XCURSOR_* env
If XCURSOR_THEME or XCURSOR_SIZE is set, use it as the cursor theme or cursor size.
This is similar to what Qt and some X11 apps do.
Due to an influx of spam, we have had to impose restrictions on new accounts. Please see this wiki page for instructions on how to get full permissions. Sorry for the inconvenience.
If XCURSOR_THEME or XCURSOR_SIZE is set, use it as the cursor theme or cursor size.
This is similar to what Qt and some X11 apps do.