After the last updates for current (X+thunderbird-31) thunderbird refused to start with the message
GLib-CRITICAL **: g_slice_set_config: assertion `sys_page_size == 0' failed.
Actually, I don't know which of the updates broke it
The workaround from: https://bugzilla.mozilla.org/show_bug.cgi?id=833117
did do what it should for me...
Setting "G_SLICE=always-malloc" does not remove the error message but allows thunderbird to start.