Somehow dev/build is not working with xdebug loaded. When calling it through the browser, it ends up with blank screen without any output. It writes the following error message into apache's log:

child pid ___ exit signal Segmentation fault (11)

Later I discovered that when removing xdebug completely from the conf makes this problem disappear. Calling dev/build with sake breaks with a "Segmentation fault". No accelerators are enabled. I don't know how to trace it. What might be causing this problem?