p3k_i9313.diff is just a workaround, not the correct fix. The problem is that PyTokenizer_FindEncoding() doesn't get the filename.
I wrote tokenizer_encoding_filename.patch which add PyTokenizer_FindEncodingFilename() and patch import.c and traceback.c to pass the filename.
Hum, I'm not sure that my patch works if the locale encoding is not UTF-8: import.c manipulates path in the filesystem encoding, whereas PyTokenizer_FindEncodingFilename() expects UTF-8 filename.
See this patch as a draft, I will try to fix the encoding issue.