Gentoo's Bugzilla –
Attachment 594510 Details for
Bug 698896kde-plasma/plasma-nm-5.17.2 - CMake Error in libs/CMakeLists.txt: Imported target "KF5::NetworkManagerQt" includes non-existent path "/usr/lib64/libffi-3.3_rc0/include" in its INTERFACE_INCLUDE_DIRECTORIES.