For converting kvm-xml to qemu-native, qemu needs to be
installed/updated in entirety.
Doing a complete "sudo make install" for qemu, will take care of the
conversion (without touching virt-manager / kvm /libvirt).
"sudo make install" (for qemu) safely updates the older qemu-files (if
any), provided the (qeemu) build has been configured via "./configure
--prefix=/usr".
Marking this thread as closed-solved.