Currently the stack alignment checking in Cyg_HardwareThread::attach_stack() only checks against a CYG_WORD. Really it should check against CYG_ALIGNMENT. However I get a strong suspicion this will cause a lot of test failures on various targets, so it's too much to deal with now. So this bug is a placeholder.
This bug has moved to http://bugs.ecos.sourceware.org/show_bug.cgi?id=29646