X crashes under Devuan Daedalus after upgrade from Chimaera

#devuan daedalus after update from chimaera on a Thinkpad R61 (Intel Core2Duo): X is crashing shortly after startx. In between it mostly does not react on mouse clicks. X.org.log tells me:

unw_get_proc_name failed: no unwind info found [-10]

two times after several error messages from libc.so.6 and crocus.dri.so, and eventually Caught signal 6 (Aborted) before it crashes.

Additionally, it tells me

client bug: timer event3 trackpoint: scheduled expiry is in the past (-30ms), your system is too slow

but I'm not sure whether there is a connection.

The web seems not very helpful. Any ideas?