nixpkgs/pkgs/development/libraries/glibc/locales.nix

/* This function builds just the `lib/locale/locale-archive' file from
   Glibc and nothing else.  If `allLocales' is true, all supported
   locales are included; otherwise, just the locales listed in
   `locales'.  See localedata/SUPPORTED in the Glibc source tree for
   the list of all supported locales:
   https://sourceware.org/git/?p=glibc.git;a=blob;f=localedata/SUPPORTED
*/

{ stdenv, buildPackages, callPackage, writeText
, allLocales ? true, locales ? [ "en_US.UTF-8/UTF-8" ]
}:

callPackage ./common.nix { inherit stdenv; } {
  name = "glibc-locales";

  builder = ./locales-builder.sh;

  outputs = [ "out" ];

  # Awful hack: `localedef' doesn't allow the path to `locale-archive'
  # to be overriden, but you *can* specify a prefix, i.e. it will use
  # <prefix>/<path-to-glibc>/lib/locale/locale-archive.  So we use
  # $TMPDIR as a prefix, meaning that the locale-archive is placed in
  # $TMPDIR/nix/store/...-glibc-.../lib/locale/locale-archive.
  buildPhase =
    ''
      mkdir -p $TMPDIR/"${buildPackages.stdenv.cc.libc.out}/lib/locale"

      echo 'C.UTF-8/UTF-8 \' >> ../glibc-2*/localedata/SUPPORTED

      # Hack to allow building of the locales (needed since glibc-2.12)
      sed -i -e 's,^$(rtld-prefix) $(common-objpfx)locale/localedef,localedef --prefix='$TMPDIR',' ../glibc-2*/localedata/Makefile
    ''
      + stdenv.lib.optionalString (!allLocales) ''
      # Check that all locales to be built are supported
      echo -n '${stdenv.lib.concatMapStrings (s: s + " \\\n") locales}' \
        | sort > locales-to-build.txt
      cat ../glibc-2*/localedata/SUPPORTED | grep ' \\' \
        | sort > locales-supported.txt
      comm -13 locales-supported.txt locales-to-build.txt \
        > locales-unsupported.txt
      if [[ $(wc -c locales-unsupported.txt) != "0 locales-unsupported.txt" ]]; then
        cat locales-supported.txt
        echo "Error: unsupported locales detected:"
        cat locales-unsupported.txt
        echo "You should choose from the list above the error."
        false
      fi

      echo SUPPORTED-LOCALES='${toString locales}' > ../glibc-2*/localedata/SUPPORTED
    '' + ''
      make localedata/install-locales \
          localedir=$out/lib/locale \
    '';

  installPhase =
    ''
      mkdir -p "$out/lib/locale"
      cp -v "$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";
}