Comment 26 for bug 1019337

Miklos, sorry for the confusion. I've figured it out now.

Breaking on gdk_x_error doesn't work at all, because the symbol is static (hence not breakable in release builds).
Breaking on _XError gives false positives, showing harmless X errors that we do actually handle and are not fatal.

The correct place to break it seems is the "exit" function:
    break exit