issue #4387 (67472) changed binascii and added tests, but the windows 
specific implementation was not changed. Change is trivial:

Index: Modules/binascii.c
===================================================================
--- Modules/binascii.c  (revision 67538)
+++ Modules/binascii.c  (working copy)
@@ -1019,7 +1019,7 @@
        Py_ssize_t len;
        unsigned int result;

-       if ( !PyArg_ParseTuple(args, "s*|I:crc32", &pbin, &crc) )
+       if ( !PyArg_ParseTuple(args, "y*|I:crc32", &pbin, &crc) )
                return NULL;
        bin_data = pbin.buf;
        len = pbin.len;