Currently the ebuild does a sed to remove '-s' from the install-command, but since it only removes it from "Makefile" it fails with the installations done my Makefile.targets. The solution? Chnage the line sed -i 's/$(INSTALL) -m 755 -s/$(INSTALL) -m 755/' Makefile to sed -i 's/$(INSTALL) -m 755 -s/$(INSTALL) -m 755/' Makefile*
It seems fixed with qemu-softmmu-0.10.1