Ah my bad, I was building against soapysdr HEAD because I was debugging a build issue with the python formula installed; this made limesuite use the 0.6 ABI instead of 0.5.x; rebuilding the released 0.5.x soapysdr and limesuite against it makes your recipe work correctly, thanks!
Now this works:
/Applications/Gqrx.app/Contents/MacOS/SoapySDRUtil --find
Thanks again and sorry for the confusion with 0.6.x!