bug#24112: xorg-server 1.18.1 is not bit-reproducible

[Danny Milosavljevic]

+             ;; The default is to use "uname -srm", which captures the kernel
+             ;; version and makes builds non-reproducible.
+             "--with-os-name=GNU"
+
+             "--with-os-vendor=GuixSD"    ;not strictly needed, but looks nice

Isn't that the wrong way around?