Add qstr_info() function and bindings for unix port.
diff --git a/py/qstr.h b/py/qstr.h
index 9224d48..779ebcb 100644
--- a/py/qstr.h
+++ b/py/qstr.h
@@ -36,3 +36,5 @@
 const char* qstr_str(qstr q);
 uint qstr_len(qstr q);
 const byte* qstr_data(qstr q, uint *len);
+
+void qstr_pool_info(uint *n_pool, uint *n_qstr, uint *n_str_data_bytes, uint *n_total_bytes);