Some time ago a updated a DHT22 library posted at AVRFreaks forum. That lib returned float values which inplies that the AVR-GCC added a very large library. The code size was above 2kB.
With this update, float number is not needed anymore and the lib returns the integral and decimal parts of the values in a defined struct format. Is needed, the user can configure the lib to return raw values from the sensor. Code size now is only around 300 bytes.