#2834: Change re module semantics, so that str and bytes mixing is forbidden,

and str (unicode) patterns get full unicode matching by default. The re.ASCII
flag is also introduced to ask for ASCII matching instead.

Modules/sre.h

@@ -30,6 +30,7 @@ typedef struct {
     PyObject* pattern; /* pattern source (or None) */
     int flags; /* flags used when compiling pattern source */
     PyObject *weakreflist; /* List of weak references */
+	int charsize; /* pattern charsize (or -1) */
     /* pattern code */
     Py_ssize_t codesize;
     SRE_CODE code[1];