Clean up glibcLocales environment handling -- manual merge of patch by wmertens (except Haskell part)

pkgs/development/libraries/glibc/locales.nix

@@ -6,7 +6,7 @@
    http://sourceware.org/cgi-bin/cvsweb.cgi/libc/localedata/SUPPORTED?cvsroot=glibc
 */
 
-{ stdenv, fetchurl, allLocales ? true, locales ? ["en_US.UTF-8/UTF-8"] }:
+{ stdenv, fetchurl, writeText, allLocales ? true, locales ? ["en_US.UTF-8/UTF-8"] }:
 
 let build = import ./common.nix; in
 
@@ -43,5 +43,10 @@ build null {
       cp -v "$TMPDIR/$NIX_STORE/"*"/lib/locale/locale-archive" "$out/lib/locale"
     '';
 
+  setupHook = writeText "locales-setup-hook.sh"
+    ''
+      export LOCALE_ARCHIVE=@out@/lib/locale/locale-archive
+    '';
+
   meta.description = "Locale information for the GNU C Library";
 }