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))
 mary</a><a href='/guix/refs/?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9'>refs</a><a class='active' href='/guix/log/etc/guix-daemon.cil.in'>log</a><a href='/guix/tree/etc/guix-daemon.cil.in?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9'>tree</a><a href='/guix/commit/etc/guix-daemon.cil.in?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9'>commit</a><a href='/guix/diff/etc/guix-daemon.cil.in?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/etc/guix-daemon.cil.in'>
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<div class='path'>path: <a href='/guix/log/?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9'>root</a>/<a href='/guix/log/etc?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9'>etc</a>/<a href='/guix/log/etc/guix-daemon.cil.in?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9'>guix-daemon.cil.in</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/etc/guix-daemon.cil.in?id=ec1a67d4ff7435fdf50de35c3f57d2f60a9cccf9&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2023-05-25 12:51:15 +0200'>2023-05-25</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=3bf612eaa13cc39caab64567660b8a02d206d19a'>etc: SELinux: Update policy file.</a><span class='msg-avail'>...<span class='msg-tooltip'>Tested on Rocky Linux 9, as discussed
at &lt;https://issues.guix.gnu.org/62487&gt;.

* etc/guix-daemon.cil.in: Add rules for /gnu/store remount and file
creation in /tmp.
</span></span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2022-12-23 20:20:06 +0100'>2022-12-23</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=afaeb657b118e6998342110deab8c8110b824417'>etc: SELinux: Allow init process to setattr on profile directories.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in: Add rule.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2022-12-23 20:20:06 +0100'>2022-12-23</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=4a134ed32e69ba888d988d2ed924a1531a54551b'>etc: SELinux: Allow daemon to search run state directories.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in: Import types init_var_run_t and
system_dbusd_var_run_t; add rules.
</span></span></td><td>Ricardo Wurmus</td></tr>
<tr><td><span title='2022-12-23 20:20:06 +0100'>2022-12-23</span></td><td><a href='/guix/commit/etc/guix-daemon.cil.in?id=f28d792719abb82cc920486e6d6f14eacc44370c'>etc: SELinux: Label guix-daemon executable in profile.</a><span class='msg-avail'>...<span class='msg-tooltip'>* etc/guix-daemon.cil.in: Add file rule for "guix-daemon" in current-guix
profile.
</span></span></td><td>Ricardo Wurmus</td></tr>