This patch is taken from debian's glibc package (generate-supported.mk).
It install the localedata/SUPPORTED file of the glibc. This file lists
all the supported locales of the glibc.

diff --git a/localedata/Makefile b/localedata/Makefile
index 65079f9eb8..14818f84e0 100644
--- a/localedata/Makefile
+++ b/localedata/Makefile
@@ -169,7 +169,8 @@ endif
 # Files to install.
 install-others := $(addprefix $(inst_i18ndir)/, \
 			      $(addsuffix .gz, $(charmaps)) \
-			      $(locales))
+			      $(locales)) \
+                   $(inst_i18ndir)/SUPPORTED
 
 tests: $(objdir)/iconvdata/gconv-modules
 
@@ -380,6 +381,14 @@ endif
 
 include SUPPORTED
 
+$(inst_i18ndir)/SUPPORTED: SUPPORTED $(+force)
+	for locale in $(SUPPORTED-LOCALES); do \
+		[ $$locale = true ] && continue; \
+		echo $$locale | sed 's,/, ,' >> LOCALES; \
+	done
+	$(make-target-directory)
+	$(INSTALL_DATA) LOCALES $@
+
 INSTALL-SUPPORTED-LOCALE-ARCHIVE=$(addprefix install-archive-, $(SUPPORTED-LOCALES))
 INSTALL-SUPPORTED-LOCALE-FILES=$(addprefix install-files-, $(SUPPORTED-LOCALES))
 >summary</a><a href='/guix/refs/?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>refs</a><a class='active' href='/guix/log/gnu/packages/storage.scm'>log</a><a href='/guix/tree/gnu/packages/storage.scm?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>tree</a><a href='/guix/commit/gnu/packages/storage.scm?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>commit</a><a href='/guix/diff/gnu/packages/storage.scm?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/gnu/packages/storage.scm'>
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<div class='path'>path: <a href='/guix/log/?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>root</a>/<a href='/guix/log/gnu?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>gnu</a>/<a href='/guix/log/gnu/packages?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>packages</a>/<a href='/guix/log/gnu/packages/storage.scm?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c'>storage.scm</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/gnu/packages/storage.scm?id=54e88d8da5ee1c0591b106b63e1c9437967ab52c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-07-23 02:00:00 +0200'>2023-07-23</span></td><td><a href='/guix/commit/gnu/packages/storage.scm?id=789f7e9a3d37135d22d0a84c987fe3877131fd06'>gnu: fuse@3: Bind to default FUSE variable.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/linux.scm (fuse): Rename this…
(fuse-2): …to this, and…
(fuse-3): …rename this…
(fuse): …to this!
(fuse-static): Rename this…
(fuse-2-static): …to this.
Adjust all users.
</span></span></td><td>Tobias Geerinckx-Rice</td></tr>
<tr><td><span title='2022-12-23 20:20:06 +0100'>2022-12-23</span></td><td><a href='/guix/commit/gnu/packages/storage.scm?id=b6d9e266a740c9706524bdd5c978f70e088675f1'>gnu: ceph: Update to 17.2.5.</a><span class='msg-avail'>...<span class='msg-tooltip'>* gnu/packages/storage.scm (ceph): Update to 17.2.5.
[source]: Remove obsolete patches; remove bundled sources for arrow.
[arguments]: Disable parallel build; use system arrow.
[inputs]: Drop input labels; add apache-thrift, apache-arrow-for-ceph, and
utf8proc.
* gnu/packages/patches/ceph-boost-compat.patch: Delete file.
* gnu/packages/patches/ceph-rocksdb-compat.patch: Delete file.
* gnu/local.mk (dist_patch_DATA): Remove them.
</span></span></td><td>Ricardo Wurmus</td></tr>