"Fix" a few places that were using PyObject_AsCharBuffer() to convert a string
(PyUnicode these days) to a char* + length.  The fix consists of calling
PyUnicode_AsString() and strlen().  This is not ideal, but AsCharBuffer()
is definitely not the API to use.
diff --git a/Modules/_sqlite/statement.c b/Modules/_sqlite/statement.c
index b80b955..a5801d6 100644
--- a/Modules/_sqlite/statement.c
+++ b/Modules/_sqlite/statement.c
@@ -50,10 +50,12 @@
     self->st = NULL;
     self->in_use = 0;
 
-    if (PyObject_AsCharBuffer(sql, &sql_cstr, &sql_cstr_len) < 0) {
+    sql_cstr = PyUnicode_AsString(sql);
+    if (sql_cstr == NULL) {
         rc = PYSQLITE_SQL_WRONG_TYPE;
         return rc;
     }
+    sql_cstr_len = strlen(sql_cstr); /* XXX */
 
     self->in_weakreflist = NULL;
     Py_INCREF(sql);
@@ -214,10 +216,12 @@
     Py_ssize_t sql_len;
     sqlite3_stmt* new_st;
 
-    if (PyObject_AsCharBuffer(self->sql, &sql_cstr, &sql_len) < 0) {
+    sql_cstr = PyUnicode_AsString(self->sql);
+    if (sql_cstr == NULL) {
         rc = PYSQLITE_SQL_WRONG_TYPE;
         return rc;
     }
+    sql_len = strlen(sql_cstr); /* XXXX */
 
     rc = sqlite3_prepare(self->db,
                          sql_cstr,