Use libc-locales-for-target

To help find the right glibc-locales to use.

guix-data-service/jobs/load-new-guix-revision.scm

@@ -1110,11 +1110,25 @@
                    inf)
     (inferior-eval '(when (defined? '%graft?) (%graft? #f)) inf)
 
-    (let* ((inferior-glibc-locales
-            (first
-             (lookup-inferior-packages inf "glibc-locales")))
-           (derivation (inferior-package-derivation store
-                                                    inferior-glibc-locales))
+    (let* ((derivation
+            (or
+             (and=>
+              (inferior-eval-with-store
+               inf
+               store
+               '(lambda (store)
+                  (and (defined?
+                         'libc-locales-for-target
+                         (resolve-module '(gnu packages base)))
+                       (derivation-file-name
+                        (package-derivation
+                         store
+                         ((@ (gnu packages base) libc-locales-for-target)))))))
+              read-derivation-from-file)
+             (inferior-package-derivation
+              store
+              (first
+               (lookup-inferior-packages inf "glibc-locales")))))
            (output (derivation->output-path derivation)))
       (close-inferior inf)
       (with-time-logging "building the glibc-locales derivation"