py/modsys: Implement sys.modules.
This for example will allow people to reload modules which didn't load
successfully (e.g. due to syntax error).
diff --git a/py/mpconfig.h b/py/mpconfig.h
index ef078d3..4d81f25 100644
--- a/py/mpconfig.h
+++ b/py/mpconfig.h
@@ -704,6 +704,11 @@
#define MICROPY_PY_SYS_MAXSIZE (0)
#endif
+// Whether to provide "sys.modules" dictionary
+#ifndef MICROPY_PY_SYS_MODULES
+#define MICROPY_PY_SYS_MODULES (1)
+#endif
+
// Whether to provide "sys.exc_info" function
// Avoid enabling this, this function is Python2 heritage
#ifndef MICROPY_PY_SYS_EXC_INFO