The following tests are currently known to fail.  After changing
source code of the library, no further failures must arise, or in
case it is clear the modification causes a different internal
behaviour (without changing the API) that is then going to be
checked by one or more testscripts, the testscripts must be
modified as well.  (An example of the latter was the modification
to malloc/free to reduce the heap when the topmost chunk had been
freed.  Several testscripts assumed the final freelist would
consist of a single large entry which is no longer the case now.)

Simulate: math/isinf-01.c atmega128 ... *** simulate failed: 22
Simulate: math/isinf-01.c at90s8515 ... *** simulate failed: 22
Simulate: math/modf-np.c atmega128 ... *** simulate failed: 47
Simulate: math/modf-np.c at90s8515 ... *** simulate failed: 47
Simulate: math/signbit-01.c atmega128 ... *** simulate failed: 2
Simulate: math/signbit-01.c at90s8515 ... *** simulate failed: 2
