d4612ef4c9
SO_LINGER controls close() behavior via struct linger
{ int l_onoff; int l_linger; }
- get returns {1, 0} (linger enabled, zero timeout)
- set accepts any value, delegates close semantics to smoltcp
Uses constant 14 since the flat Redox namespace can't use
Linux level SOL_SOCKET=13 (collides with TCP_CONGESTION=13).
All 31 tests pass.