vfprintf.c patch

[Doug Evans]

Joel Sherrill writes:
 > 
 > Minor modification to trick gcc into avoiding referencing
 > a floating point register unless someone really tries
 > to print a floating point number.  On the PowerPC gcc
 > will save a FP register all the time without this patch.
 > 
 > The ideal solution would be to break out the FP printing 
 > into a separate function but that was more risky to implement.

Already done, but the other way around.
IIRC, see iprintf vs printf.