Vodz' last_patch31

Very minimal last corrections:

    1) busybox.c: fix warining
    2) docs/: add applets for list from pwd_grp
    3) usage.h: add -n option for route
    4) run_parts.c: many todo fix for busybox style
    5) addgroup.c: add #ifdef CONFIG_FEATURE_SHADOWPASSWDS, reduce one
    perror_msg
    6) adduser.c: fix bug "variable i not initialize" and
       add #ifdef CONFIG_FEATURE_SHADOWPASSWDS

applets/busybox.c

@@ -35,7 +35,7 @@ typedef int (*__link_f)(const char *, const char *);
  *		malloc'd string w/ full pathname of busybox's location
  *		NULL on failure
  */
-static char *busybox_fullpath()
+static char *busybox_fullpath(void)
 {
 	return xreadlink("/proc/self/exe");
 }