Harri, Thanks for the bug report. I can confirm this bug for my sid system as well. One question: are you running Gnome?
I noticed after some upgrade some day (not sure which day, which upgrade) that my cursor theme stopped appearing for Gnome. I asked around and no one was confirming this for me, until I found your report on the BTS. The thing that boggles my mind about this bug is that the few KDE apps I run (K3B for example) were picking up my custom cursors from the Freedesktop.org defined spot (~/.icons) but Gnome was not. Once I symlinked libXcursor.so to libXcursor.so.1.0.1, Gnome was working as well. That's why I ask if you run Gnome. Or, more specifically, I'm trying to figure out if this is a libxcursor bug, or a Gnome bug. I'm not really sure. Don't know enough about it. But, the real bottom line is: bug confirmed. At least for a fix, the libxcursor maintainer should create your symlink to make KDE and Gnome both happy. Can any KDE users report on their experience with the current libxcursor, and perhaps check if Gnome is working with it or not? -Andrew