locale: symlink identical langpack LC_CTYPEs to the C.utf8 version

Almost half the LC_CTYPE files in langpacks are identical to the C.utf8
variant which is installed by default.  This commit converts these to
symbolic links instead, saving ~350K of installed size per langpack.

Reviewed-by: Florian Weimer <fweimer@redhat.com>

glibc.spec

@@ -152,7 +152,7 @@ end \
 Summary: The GNU libc libraries
 Name: glibc
 Version: %{glibcversion}
-Release: 2%{?dist}
+Release: 3%{?dist}
 
 # In general, GPLv2+ is used by programs, LGPLv2+ is used for
 # libraries.
@@ -1223,6 +1223,20 @@ popd
 # via hardlinks, so we must group them ourselves.
 hardlink -c %{glibc_sysroot}/usr/lib/locale
 
+# Almost half the LC_CTYPE files in langpacks are identical to the C.utf8
+# variant which is installed by default.  When we keep them as hardlinks,
+# each langpack ends up retaining a copy.  If we convert these to symbolic
+# links instead, we save ~350K each when they get installed that way.
+#
+# LC_MEASUREMENT and LC_PAPER also have several duplicates but we don't
+# bother with these because they are only ~30 bytes each.
+pushd %{glibc_sysroot}/usr/lib/locale
+for f in $(find eo *_* -samefile C.utf8/LC_CTYPE); do
+  rm $f && ln -s '../C.utf8/LC_CTYPE' $f
+done
+popd
+
+
 # install_different:
 #	Install all core libraries into DESTDIR/SUBDIR. Either the file is
 #	installed as a copy or a symlink to the default install (if it is the
@@ -2160,6 +2174,9 @@ update_gconv_modules_cache ()
 %files -f compat-libpthread-nonshared.filelist -n compat-libpthread-nonshared
 
 %changelog
+* Tue Feb 15 2022 Arjun Shankar <arjun@redhat.com> - 2.35.9000-3
+- Reduce installed size of some langpacks by de-duplicating LC_CTYPE
+
 * Thu Feb 10 2022 Arjun Shankar <arjun@redhat.com> - 2.35.9000-2
 - Drop glibc-fedora-localedef.patch and adjust locale installation
   accordingly so that installed content remains unchanged.