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.old b/localedata/Makefile
index 34877c0..a61d9b9 100644
--- a/localedata/Makefile.old
+++ b/localedata/Makefile
@@ -91,7 +91,8 @@ endif
 # Files to install.
 install-others := $(addprefix $(inst_i18ndir)/, \
 			      $(addsuffix .gz, $(charmaps)) \
-			      $(locales))
+			      $(locales)) \
+                   $(inst_i18ndir)/SUPPORTED
 
 tests: $(objdir)/iconvdata/gconv-modules
 
@@ -195,6 +196,14 @@ 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 $@
+
 INSTALL-SUPPORTED-LOCALES=$(addprefix install-, $(SUPPORTED-LOCALES))
 
 # Sometimes the whole collection of locale files should be installed.
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<div class='path'>path: <a href='/guix/log/?id=72ca1a336ab296187a4d025c399fade63004c780'>root</a>/<a href='/guix/log/po?id=72ca1a336ab296187a4d025c399fade63004c780'>po</a>/<a href='/guix/log/po/packages?id=72ca1a336ab296187a4d025c399fade63004c780'>packages</a>/<a href='/guix/log/po/packages/ko.po?id=72ca1a336ab296187a4d025c399fade63004c780'>ko.po</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/po/packages/ko.po?id=72ca1a336ab296187a4d025c399fade63004c780&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2024-02-29 22:57:09 +0100'>2024-02-29</span></td><td><a href='/guix/commit/po/packages/ko.po?id=956f44b931f050fbffca51737000b9049808b3ca'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>Change-Id: Ic1506db5813880153b6def005011618dc4529e8f
</span></span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-05-31 17:23:21 +0200'>2023-05-31</span></td><td><a href='/guix/commit/po/packages/ko.po?id=8e9e6a6482f3ba98d1cdcad344ee488e8751fee7'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* doc/guix-cookbook.texi (Top): Mention Slovak.
</span></span></td><td>Florian Pelz</td></tr>
<tr><td><span title='2023-03-07 21:14:57 +0100'>2023-03-07</span></td><td><a href='/guix/commit/po/packages/ko.po?id=d333958763b0840c4cd895601b079b68358a6a46'>nls: Update translations.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-12-04 22:25:23 +0100'>2022-12-04</span></td><td><a href='/guix/commit/po/packages/ko.po?id=2e75b328b6bbdadbffe5b643a4891b5026a0defd'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>po/packages/vi.po: New file.
po/packages/LINGUAS: Add it.
</span></span></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2022-11-04 10:56:38 +0100'>2022-11-04</span></td><td><a href='/guix/commit/po/packages/ko.po?id=a65ce9dd500460af4f97e7398fb35dd817f4c677'>nls: Update translations.</a><span class='msg-avail'>...<span class='msg-tooltip'>* po/guix/lt.po: New file.
* po/guix/LINGUAS: Add lt.
</span></span></td><td>Julien Lepiller</td></tr>