Rename PyUnicode_AsString -> _PyUnicode_AsString and
PyUnicode_AsStringAndSize -> _PyUnicode_AsStringAndSize to mark
them for interpreter internal use only.

We'll have to rework these APIs or create new ones for the
purpose of accessing the UTF-8 representation of Unicode objects
for 3.1.
diff --git a/Modules/_sqlite/statement.c b/Modules/_sqlite/statement.c
index fb1eec7..d2f3c1e 100644
--- a/Modules/_sqlite/statement.c
+++ b/Modules/_sqlite/statement.c
@@ -59,7 +59,7 @@
     self->st = NULL;
     self->in_use = 0;
 
-    sql_cstr = PyUnicode_AsStringAndSize(sql, &sql_cstr_len);
+    sql_cstr = _PyUnicode_AsStringAndSize(sql, &sql_cstr_len);
     if (sql_cstr == NULL) {
         rc = PYSQLITE_SQL_WRONG_TYPE;
         return rc;
@@ -140,7 +140,7 @@
             rc = sqlite3_bind_double(self->st, pos, PyFloat_AsDouble(parameter));
             break;
         case TYPE_UNICODE:
-            string = PyUnicode_AsString(parameter);
+            string = _PyUnicode_AsString(parameter);
             rc = sqlite3_bind_text(self->st, pos, string, -1, SQLITE_TRANSIENT);
             break;
         case TYPE_BUFFER:
@@ -296,7 +296,7 @@
     Py_ssize_t sql_len;
     sqlite3_stmt* new_st;
 
-    sql_cstr = PyUnicode_AsStringAndSize(self->sql, &sql_len);
+    sql_cstr = _PyUnicode_AsStringAndSize(self->sql, &sql_len);
     if (sql_cstr == NULL) {
         rc = PYSQLITE_SQL_WRONG_TYPE;
         return rc;