Fix for PR#56 -- there is a kludge to modify the exponent for
a converted value of zero, due to the way that SANE special-
cases it. This kludge was applied for all values that had a
zero exponent; now do it only for the value zero.
The ecvt(), fcvt(), and __dtoa() routines were generally
rewritten to address the problem of printing floating point
numbers (they sometimes came out wrong, especially representations
of zero).
__dtoa was written from the description in the BSD sources (note
that the comment of it being "like ecvt/fcvt other than truncating
trailing zeros") is not quite accurate where it comes to the rve
pointer or the printing of zero values. __dtoa is still expected
to be wrong for any modes other than 2 and 3, however those modes
are not used by anything in libc yet. Fix them when they pop up.
BSD has not ecvt/fcvt routines, so these have been written based
on the man page and observed behavior of the Linux implementation.
There is no gcvt yet.
