vfprintf, scanf portability

[Karl Berry]

The GNU coding standards have had these two items since the beginning.

First:
    Don't use the return value of @code{sprintf}.  It returns the number of
    characters written on some systems, but not on all systems.

I don't see this mentioned in the Gnulib entry for sprintf at
  http://www.gnu.org/software/gnulib/manual/html_node/sprintf.html
Is it still relevant?

Second:
    Be aware that @code{vfprintf} is not always available.

Again, I don't see it mentioned in
  http://www.gnu.org/software/gnulib/manual/html_node/vfprintf.html 
though seemingly nearly every other system has some kind of problem.
Is it still relevant?

(Reuben and I are trying to rewrite that node among others.)

Thanks,
karl