Handling null pointers to printf

[Aaron Stone]

Hi,

When glibc gets a null pointer in one of the printf-family of functions
for a %s argument, it prints "(null)" and doesn't crash. All of the
*BSD's libc's also print "(null)". 

Gnulib, when using its own vasnprintf implementation, does crash. The
principal offender is Solaris, for which a) this would normally crash
their in libc, and b) downstream gnulib consumers prefer to use gnulib
rather than the Solaris printf's on Solaris anyways.

I believe that Gnulib should mimic the Linux and *BSD way of handling
null %s args without crashing.

This patch, submitted to Glib last May, appears to correct this:
http://mail.gnome.org/archives/gtk-devel-list/2005-May/msg00031.html

Thanks,
Aaron