Hi!

The commit

    56759d30d9a817a9c9221c9468a4c4a59c9a4713
    gnu: Switch to GCC 11.

introduced a gratuitous dependency on coreutils-boot0 to gcc-boot0 by
adding this atypical snippet

--8<---------------cut here---------------start------------->8---
        (snippet
         #~(begin
             ;; XXX: The GCC test suite contains files with non-ASCII file
             ;; names, which cannot be repacked by BOOTSTRAP-ORIGIN.  Nor
             ;; can it be deleted from Guile, so resort to this evil hack.
             #$(origin-snippet (package-source gcc))
             (system* #$(file-append coreutils-boot0 "/bin/rm") "-rf"
                      "gcc/testsuite/go.test/test/fixedbugs/issue27836.dir"))))))
--8<---------------cut here---------------end--------------->8---

This is problematic, because coreutils-boot0 doesn't build for the Hurd:
coreutils needs hurd headers, and our hurd-headers-boot0 depends
on...coreutils-boot0.

Why was coreutils-boot0 used instead of the canonical
delete-file-recursively?

Anyway, as a first attempt, I tried adding

--8<---------------cut here---------------start------------->8---
(define gcc-boot0/hurd
  ;; gcc-boot0 adds a dependency on coreutils-boot0, which does not build on
  ;; the Hurd.  Move this origin definition to gcc-boot0 and remove
  ;; gcc-boot0/hurd in the next rebuild cycle.
  (package
    (inherit gcc-boot0)
    (source
     (bootstrap-origin
      (origin
        (inherit (package-source gcc))
        (snippet
         #~(begin
             ;; XXX: The GCC test suite contains files with non-ASCII file
             ;; names, which cannot be repacked by BOOTSTRAP-ORIGIN.  Nor
             ;; can it be deleted from Guile, so resort to this evil hack.
             #$(origin-snippet (package-source gcc))
             (delete-file-recursively
              "gcc/testsuite/go.test/test/fixedbugs/issue27836.dir"))))))))
--8<---------------cut here---------------end--------------->8---

and use that in %boot1-inputs...but as gcc-boot0 is used in more places
that doesn't really work.

So, until we can correct the gcc-boot0 snippet problem in the next
rebuild cycle (how does that work now that we don't have core-updates
anymore?, I made coreutils-boot0 build on the Hurd.  See the patch
below.

Using this patch, I've just succeeded to build gcc-boot0:

--8<---------------cut here---------------start------------->8---
root@guixydevel ~/src/guix/wip-hurd# ./pre-inst-env guix build -e '(@@ (gnu packages commencement) gcc-boot0)' --verbosity=1
The following derivation will be built:
  /gnu/store/669gwbfc96k5r8rv06d4cd10q7kpnkqn-gcc-cross-boot0-11.3.0.drv

building /gnu/store/669gwbfc96k5r8rv06d4cd10q7kpnkqn-gcc-cross-boot0-11.3.0.drv...
/gnu/store/3hl61ndnzqjrr07rywh2mfw58k81jchy-gcc-cross-boot0-11.3.0-lib
/gnu/store/wbdza27aq1mab8blvswvd0g28n5pk982-gcc-cross-boot0-11.3.0
--8<---------------cut here---------------end--------------->8---

but now `guix build hello' seems to hang, so it a circular dependency
might have been introduced somewhere.  What a mess...

WDYT?

Greetings,
Janneke