Fix invalid ptr assignment for --enable-static builds

Also changes the default to set $HOME to / instead of nothing.  This can
of course be improved immensely.  Pull requests always welcome ;-)

Signed-off-by: Joachim Nilsson <troglobit@gmail.com>

helpers.c

@@ -216,7 +216,7 @@ void logit(int prio, const char *fmt, ...)
 int getuser(char *username, char **home)
 {
 #ifdef ENABLE_STATIC
-	home = NULL;		/* XXX: Fixme */
+	*home = "/";		/* XXX: Fixme */
 	return fgetint("/etc/passwd", "x:\n", username);
 #else
 	struct passwd *usr;