Fix undefined int shift

[Jeff Johnston]

Patch committed.

-- Jeff J.

----- Original Message -----
> My analysis here applies:
> 
> https://marc.info/?l=openbsd-tech&m=145377854103866&w=2
> 
> Thanks for your time,
> Michael
> 
> 
> diff --git a/newlib/libc/sys/linux/net/ifname.c
> b/newlib/libc/sys/linux/net/ifname.c
> index b7975bc..d2609b1 100644
> --- a/newlib/libc/sys/linux/net/ifname.c
> +++ b/newlib/libc/sys/linux/net/ifname.c
> @@ -125,7 +125,8 @@ struct if_nameindex *
>  if_nameindex()
>  {
>  	size_t needed;
> -	int mib[6], i, ifn = 0, off = 0, hlen;
> +	int mib[6], ifn = 0, off = 0, hlen;
> +	unsigned int i;
>  	char *buf = NULL, *lim, *next, *cp, *ifbuf = NULL;
>  	struct rt_msghdr *rtm;
>  	struct if_msghdr *ifm;
>