uv_if_indextoname() is used to convert an IPv6 scope_id
to an interface identifier string such as %eth0 or %lo.
uv_if_indextoiid() returns an IPv6 interface identifier.
On Unix it calls uv_if_indextoname(). On Windows it uses
snprintf() to return the numeric interface identifier as
a string.
Refs: https://github.com/nodejs/node/pull/14500
PR-URL: https://github.com/libuv/libuv/pull/1445
Reviewed-By: Santiago Gimeno <santiago.gimeno@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>