A bug in the current _M_insert_float/_M_group_float

[Paolo Carlini]

Hi,

I think there is a bug, which, however, probably I'm not going to
fix since we are in the process of replacing all of this with the
fast code adapted from v2. But it may be worth pointing it out,
also to be sure that we do this right in the new framework.

Basically, in _M_group_float, if __p is NULL - this means that no
decimal digit was found - the whole [__cs, __cs + __len) is considered
for grouping, irrespective of the use of a scientific notation!

Paolo.

P.S. Hummm, first blush the problem is present also in the last
version I have of Jerry's code... Jerry?