lwip update breaks mini-apps/daytime build

[razvancojocaru]

After having built the toolchain, i tried to build the daytime app from mini-apps noxs branch.

Building the daytime app was unsuccessful, with errors referring to lwip headers:

[...]
/home/razvan/minios/mini-apps/daytime/daytime.c:17:20: error: storage size of ‘listenaddr’ isn’t known
     struct ip_addr listenaddr = { 0 };
                    ^
/home/razvan/minios/mini-apps/daytime/daytime.c:26:16: error: variable ‘ipaddr’ has initializer but incomplete type
         struct ip_addr ipaddr = { htonl(0x0a000001) };
                ^
/home/razvan/minios/mini-apps/daytime/daytime.c:26:24: error: storage size of ‘ipaddr’ isn’t known
         struct ip_addr ipaddr = { htonl(0x0a000001) };
[...]

After reverting the lwIP: Point to CNPLAB's clone of lwIP commit, the daytime build was successful. I'm not sure why the CNPLAB clone breaks daytime or if any other apps are affected by the same change.