Use overridable bson_errprintf for printing to stderr.
Use overridable bson_errprintf for printing to stderr.

Elastica/mongo-c-driver-legacy,Elastica/mongo-c-driver-legacy,HeliumProject/mongo-c,mongodb/mongo-c-driver-legacy,HeliumProject/mongo-c,mongodb/mongo-c-driver-legacy,HeliumProject/mongo-c,mongodb/mongo-c-driver-legacy,Elastica/mongo-c-driver-legacy,Elastica/mongo-c-driver-legacy,mongodb/mongo-c-driver-legacy,HeliumProject/mongo-c