try to fallback to pysqlite2.dbapi2 as sqlite3

for situations where Python is built without sqlite3 and
can not easily be changed, it would be nice to still be
able to get history with pysqlite2.

IPython/core/history.py

@@ -20,6 +20,9 b' import re'
 try:
     import sqlite3
 except ImportError:
+    try:
+        from pysqlite2 import dbapi2 as sqlite3
+    except ImportError:
     sqlite3 = None
 import threading