extmod/modlwip: slip: Use stream protocol and be port-independent.
Based on the original patch by Galen Hazelwood:
https://github.com/micropython/micropython/pull/1517 .
diff --git a/py/mpstate.h b/py/mpstate.h
index dd185a7..9a8cc02 100644
--- a/py/mpstate.h
+++ b/py/mpstate.h
@@ -127,6 +127,11 @@
// include any root pointers defined by a port
MICROPY_PORT_ROOT_POINTERS
+ // root pointers for extmod
+ #if MICROPY_PY_LWIP_SLIP
+ mp_obj_t lwip_slip_stream;
+ #endif
+
//
// END ROOT POINTER SECTION
////////////////////////////////////////////////////////////