stmhal: Collect all root pointers together in 1 place.
A GC in stmhal port now only scans true root pointers, not entire BSS.
This reduces base GC time from 1700ms to 900ms.
diff --git a/esp8266/mpconfigport.h b/esp8266/mpconfigport.h
index fbf77f6..7d1d6e1 100644
--- a/esp8266/mpconfigport.h
+++ b/esp8266/mpconfigport.h
@@ -61,6 +61,11 @@
#define MICROPY_PORT_BUILTIN_MODULES \
{ MP_OBJ_NEW_QSTR(MP_QSTR_pyb), (mp_obj_t)&pyb_module }, \
+#define MP_STATE_PORT MP_STATE_VM
+
+#define MICROPY_PORT_ROOT_POINTERS \
+ const char *readline_hist[8];
+
// We need to provide a declaration/definition of alloca()
#include <alloca.h>