POSIX.1-2008 tightened the definition of NULL to be 0 cast to the
type 'void *'.
Defining NULL as 0 is problematic, because it requires users to
cast NULL to a pointer type before passing it to variadic
functions. Using POSIX's definition is safer, because NULL can be
used in all contexts without a cast, due to the alignment of
'void *' and 'char *' being the same. It also helps the compiler
be able to detect when NULL is being used in an integer context.
Link: <http://ewontfix.com/11/>
Signed-off-by: Alejandro Colomar <alx.manpages@gmail.com>
