After a clean guix make, guix system build produced this error ...

root@g1 ~/con/15# guix system --cores=4 --max-jobs=4 -K --on-error=debug build sys.scm
guix system: error: qemu-CVE-2017-7493.patch: patch not found

VERSION INFO:

root@g1 ~/con/15# guix --version
guix (GNU Guix) 0.13.0.4202-1f6f4
Copyright (C) 2017 the Guix authors
License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

root@g1 ~/con/15# stat ~/.config/guix/latest | grep File:
  File: /root/.config/guix/latest -> /home/g1/src/guix/

root@g1 ~/con/15# git -C ~/.config/guix/latest describe
v0.13.0-4202-g1f6f4c40c

root@g1 ~/con/15# git -C ~/.config/guix/latest log -n 1 --oneline
1f6f4c40c (HEAD -> o-master, origin/master, origin/HEAD) gnu: Add r-tgconfig.

root@g1 ~/con/15# git -C /home/g1/src/guix branch -av | grep '*'
* o-master                                1f6f4c40c gnu: Add r-tgconfig.

SYS CONFIG: