Thank you Ludo,
I added guile-semver to guix in the attached patch set, and I tested it 
by running ./pre-inst-env guix environment guix, which installed the 
guile-semver.

> and Makefile.am may have to check whether guile-semver is available.)

I didn't see anything in the Makefile.am that looks to check for guile 
modules. Let me know if anything needs fixing!

=Martin