bug#73065: glibc-supported-locales needs zstd

[Ricardo Wurmus]

I'm trying to build the installer with

    guix system image -t iso9660 gnu/system/install.scm

This fails:

    build of 
/gnu/store/64r5f7ikrjwzs9bslhfabv1p8r5gzk83-glibc-supported-locales.scm.drv 
failed

--8<---------------cut here---------------start------------->8---
tar (child): zstd: Cannot exec: No such file or directory
tar (child): Error is not recoverable: exiting now
tar: Child returned status 2
tar: Error is not recoverable: exiting now
Backtrace:
           3 (primitive-load "/gnu/store/3jkscaxiws5q79bhyklw9y65qib?")
In ice-9/eval.scm:
    619:8  2 (_ #f)
In guix/build/gnu-build-system.scm:
   208:10  1 (unpack #:source _)
In guix/build/utils.scm:
    822:6  0 (invoke "tar" "xvf" "/gnu/store/3rqf5bv8zl4wdy1vmgzsfwq?")

guix/build/utils.scm:822:6: In procedure invoke:
ERROR:
  1. &invoke-error:
      program: "tar"
      arguments: ("xvf" 
"/gnu/store/3rqf5bv8zl4wdy1vmgzsfwqiw094x3pv-glibc-2.39.tar.zst")
      exit-status: 2
      term-signal: #f
      stop-signal: #f
--8<---------------cut here---------------end--------------->8---

Looking at gnu/system/locale.scm I can see that the PATH does not
include zstd but only xz.

Adding

     #+(file-append zstd "/bin") ":"

to the PATH definition in glibc-supported-locales fixed this for me.

-- 
Ricardo