objstrunicode: Re-add buffer protocol back for now, required for io.StringIO.
diff --git a/py/objstr.c b/py/objstr.c
index 39b0359..acbf002 100644
--- a/py/objstr.c
+++ b/py/objstr.c
@@ -1601,7 +1601,7 @@
 }
 #endif
 
-STATIC machine_int_t str_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, int flags) {
+machine_int_t str_get_buffer(mp_obj_t self_in, mp_buffer_info_t *bufinfo, int flags) {
     if (flags == MP_BUFFER_READ) {
         GET_STR_DATA_LEN(self_in, str_data, str_len);
         bufinfo->buf = (void*)str_data;