guest kernel build (config quick-cycle, -j6, 6 vCPU):
cd /usr/src/sys/config && config -d /usr/obj/usr/src/sys/X86_64_GENERIC X86_64_GENERIC
cd /usr/obj/usr/src/sys/X86_64_GENERIC && make -j6 && make install
===> libiconv
BUILD_INSTALL_OK
(full log on guest /root/fixbuild.log; zero errors)