bugs in printf and related functions

The implementation of vsnprinft in /lib/rtl/printf.c lacks
support for float-point number (i.e.: f,g,E,e,o output types)

This is the cause of the failure of some Wine's test (see attached file)

The current implementation is based on the implementation in the linux
kernel (in /lib/vsprintf.c), though there are some small differencies.

May be we can look how float-point output is implemented in glibc