forked from Imagelibrary/lwip
* Socket functions definitions moved out of the #define LWIP_SOCKET_EXTERNAL_HEADERS as all users who set LWIP_SOCKETS to 1 will need them regardless they use lwip's or external socket headers.
* Socket functions definitions moved out of the #define LWIP_SOCKET_EXTERNAL_HEADERS as all users who set LWIP_SOCKETS to 1 will need them regardless they use lwip's or external socket headers.