Fixes <https://bugs.gnu.org/34276>. Reported by Tobias Geerinckx-Rice <me@tobias.gr>. * gnu/system/vm.scm (expression->derivation-in-linux-vm)[loader]: Produce '/xchg/.exit-status' file upon success. * gnu/build/vm.scm (load-in-linux-vm): Check for 'xchg/.exit-status' once QEMU has completed and respond accordingly.