dev-qt/qtnfc seems not to be packaged. dev-qt/qtbluetooth builds qtconnectivity, but removes nfc support "the hard way" (with sed). Potentially, having dev-qt/qtconnectivity with use flags to activate bluetooth or nfc might be the best solution. qtnfc is a dependency of AusweisApp2 ( https://github.com/Governikus/AusweisApp2 ) which is not packaged yet.
Ebuild in bug 344941 and guru overlay does not seem to require this package: https://gitweb.gentoo.org/repo/proj/guru.git/tree/sys-auth/AusweisApp2/AusweisApp2-9999.ebuild
Interesting find! Yes, indeed. Checking the build system, it seems this was effectively only ever needed for NFC on iOS and Android, and at some point in the past year, the CMake logic was also fixed to only require it if building for these targets. So I'll close this request for good, thanks! :-)
