I would like to use some software packages, such as rtl_433, that are written with the RTL-SDR library with a FUNcube Dongle instead. Is there a wrapper that would allow the FUNcube Dongle to be used with RTL-SDR?
The librtlsdr is for RTL2832U based DVB-T dongles. The Funcube Dongle has no RTL2832U chip. However, the overarching OSMOSDR project includes support for the Funcube Dongles (Pro and Pro+) and other SDR equipment. See http://sdr.osmocom.org/trac/wiki/GrOsmoSDR for more information.