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=8baaf51f0a6891cc2fb34928dab2337b627218c5&amp;showmsg=1'>root</a>/<a href='/guix/log/.mailmap?id=8baaf51f0a6891cc2fb34928dab2337b627218c5&amp;showmsg=1'>.mailmap</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/.mailmap?id=8baaf51f0a6891cc2fb34928dab2337b627218c5'>Collapse</a>)</th><th class='left'>Author</th></tr>
<tr class='logheader'><td><span title='2020-01-17 18:30:33 +0100'>2020-01-17</span></td><td class='logsubject'><a href='/guix/commit/.mailmap?id=a3143063aeeecb5c02f75a6e1ddc0cc295e0e4f8'>Update email address for Amin Bandali.</a></td><td>Amin Bandali</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* .mailmap: Add name and email addresses for Amin Bandali.
* gnu/local.mk, gnu/packages/emacs-xyz.scm, gnu/packages/emacs.scm,
gnu/packages/fpga.scm, gnu/packages/lean.scm, gnu/packages/maths.scm:
Update email address for Amin Bandali.

Signed-off-by: Tobias Geerinckx-Rice &lt;me@tobias.gr&gt;


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<tr class='logheader'><td><span title='2019-12-19 11:35:23 -0600'>2019-12-19</span></td><td class='logsubject'><a href='/guix/commit/.mailmap?id=4b3ff36228da17db980c98fe9e1669be613a5402'>Update email for Brett Gilio.</a></td><td>Brett Gilio</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* .mailmap: Add name and email for Brett Gilio.
* gnu/local.mk, gnu/packages/admin.scm, gnu/packages/audio.scm,
  gnu/packages/bittorrent.scm, gnu/packages/build-tools.scm,
  gnu/packages/cran.scm, gnu/packages/emacs-xyz.scm,
  gnu/packages/messaging.scm, gnu/packages/python-xyz.scm,
  gnu/packages/sml.scm, gnu/packages/terminals.scm, gnu/packages/wm.scm:
  Update email for Brett Gilio.


</td></tr>
<tr class='logheader'><td><span title='2019-12-18 22:57:44 -0600'>2019-12-18</span></td><td class='logsubject'><a href='/guix/commit/.mailmap?id=a7cdf124c0b28be6c4e750161c1341753eede7b8'>gnu: leocad: Update to 19.07.1.</a></td><td>Eric Bavier</td></tr>
<tr class='nohover-highlight'><td/><td colspan='3' class='logmsg'>
* gnu/packages/lego.scm (leocad): Update to 19.07.1
[source]: Use git-fetch.
* .mailmap: Add preferred alias for myself.


</td></tr>