Fixes issue #2399 by optionally returning a SocketAddress from
TCPServer::accept().
This entails changes to underlying NetworkStack and nsapi. This
commit deals only with lwip and higher level APIs; other users of
NetworkStack and nsapi may be affected. Currently lwip is the only
in-tree user of nsapi.
Currently this uses the same mechanism used by the rtos to conditionally
include the network-socket API. Perhaps this should be builtin to the
config system?
Note: this does require that the bug-compatible inclusion of mbed.h
be removed to avoid include-order issues.
per @sg-
Expression needed to init to zero a simple POD struct
Before (valid in C99/C++11/G++): (nsapi_addr_t){}
After (valid in C++03, invalid in C): nsapi_addr_t()
Colin Hogben
Christopher Haster