Dynamic arrays allocation size

["Luís]

BTW, as far as I can see the overflow/underflow behavior never 
got specified by the language, in any case:

1) http://forum.dlang.org/thread/jo2c0a$31hh$1@digitalmars.com 
<-- no conclusion

2) Andrei's book doesn't seem to mention the topic.

If it is specified somewhere please do tell. Whatever the 
behavior should be (unspecified, modulus for unsigned integers, 
etc) there really should be an official stance.