QString::vasprintf() doesn't support the '#' flag in format specifiers

Standard printf-family functions support a # modifier flag to format specifiers:

1. Specifies that the value is to be converted to an
   alternative form. For o conversion, it shall increase the
   precision, if and only if necessary, to force the first
   digit of the result to be a zero (if the value and precision
   are both 0, a single 0 is printed). For x or X conversion
   specifiers, a non-zero result shall have 0x (or 0X) prefixed
   to it. For a, A, e, E, f, F, g, and G conversion specifiers,
   the result shall always contain a radix character, even if
   no digits follow the radix character. Without this flag, a
   radix character appears in the result of these conversions
   only if a digit follows it. For g and G conversion
   specifiers, trailing zeros shall not be removed from the
   result as they normally are. For other conversion
   specifiers, the behavior is undefined.

However, QString::vasprintf() does not support this modifier; hence, nor does either QString::asprintf() or qsnprintf().