Vivien,

Thanks!  I've pushed this series as 
df2404482495bc3af03e7fc902af1e6b0d10b4a4 et al.

I made a only few small tweaks, mainly to the commit message:

> gnu: minetest-basic-materials: Depend on minetest-moreores.

‘Depend’ sounds wrong to me; it either does, or it doesn't, we 
don't determine that.  Changed to ‘Propagate …’

> * minetest.scm (minetest-basic-materials): Add minetest-moreores 
> as a propagated input.

Keep Git commit message body lines <=72 characters.  Most 
(non-Guix) tooling is built around that assumption.

Also use full relative file names, and use [field] notation where 
appropriate:

  * gnu/packages/foo.scm (foo)[propagated-inputs]: Add bar.

For the build system patches, I changed

> guix: minetest-build-system: […]

to

  build-system/minetest: […]

Why?  Because it's shorter.  Is this a documented rule?  I can't 
say!

> ;; basic_materials:silver_wire cannot be crafted without
> ;; moreores:silver_ingot.

Documenting this is a great idea.

> (commit "0b6f669df4c9b7771c03e0e6ba8effb471cdfcae")))

I changed this to

  (commit (string-append "v" version))

to use the git tag.

Both have advantages & disadvantages, but this is our currently 
preferred style.

> (synopsis "Adds new ore types")
> (description "More ores for Minetest.")

These aren't acceptable.  See (guix)Synopses and Descriptions.

This was my attempt at improving the importer's lazywork:

  (synopsis "Additional ore types, tools, swords, and rails for 
  Minetest")
  (description
   "This Minetest mod adds new ore types to the game (mithril, 
   silver) as well
as swords and tools made of different materials.  It also adds 
copper rails.")

Bit vague, but you know why.

Closing; thanks!

T G-R