Dear Guix,

orbit2 is a dependency for libreoffice, and it does not build
reproducibly on core-updates-frozen (I don’t know on master). The issue
is well-known, for instance here on Arch:
https://bbs.archlinux.org/viewtopic.php?id=240775

I applied the fix, and it builds with parallel make. What do you think?

Vivien