Disable $ numberLong for 64-bit int values ​​when converting BSON to JSON

Question

I am using the BSON mongodb C ++ library. I recently updated to use mongodb 3.0, and now BSON serialization with 64 bit ints gives:

{"time": {"$numberLong": "123"}} 

when i call it:

 BSON("time" << time).jsonString() 

My client code cannot handle this and needs json instead:

 {"time": 123} 

How do I get the old mongodb 2.4 behavior?