diff --git a/pkgs/build-support/cabal/default.nix b/pkgs/build-support/cabal/default.nix
index 7f4d431c0076..a1dc68e6484a 100644
--- a/pkgs/build-support/cabal/default.nix
+++ b/pkgs/build-support/cabal/default.nix
@@ -1,6 +1,6 @@
 # generic builder for Cabal packages
 
-{ stdenv, fetchurl, lib, pkgconfig, ghc, Cabal, jailbreakCabal
+{ stdenv, fetchurl, lib, pkgconfig, ghc, Cabal, jailbreakCabal, glibcLocales
 , enableLibraryProfiling ? false
 , enableCheckPhase ? true
 }:
@@ -112,6 +112,10 @@ assert enableCheckPhase -> stdenv.lib.versionOlder "7" ghc.ghcVersion;
               (stdenv.lib.enableFeature self.enableSplitObjs "split-objs")
             ] ++ stdenv.lib.optional (stdenv.lib.versionOlder "7" ghc.ghcVersion) (stdenv.lib.enableFeature self.doCheck "tests");
 
+            # GHC needs the locale configured during the Haddock phase.
+            LANG = "en_US.UTF-8";
+            LOCALE_ARCHIVE = lib.optionalString stdenv.isLinux "${glibcLocales}/lib/locale/locale-archive";
+
             # compiles Setup and configures
             configurePhase = ''
               eval "$preConfigure"
@@ -150,11 +154,7 @@ assert enableCheckPhase -> stdenv.lib.versionOlder "7" ghc.ghcVersion;
               ./Setup build
 
               export GHC_PACKAGE_PATH=$(${ghc.GHCPackages})
-              if [ -z "$noHaddock" ]; then
-                export LANG="en_US.UTF-8"
-                ./Setup haddock
-                unset LANG
-              fi
+              test -n "$noHaddock" || ./Setup haddock
 
               eval "$postBuild"
             '';
diff --git a/pkgs/top-level/haskell-packages.nix b/pkgs/top-level/haskell-packages.nix
index 07623af281fa..44b616667492 100644
--- a/pkgs/top-level/haskell-packages.nix
+++ b/pkgs/top-level/haskell-packages.nix
@@ -105,6 +105,7 @@ let result = let callPackage = x : y : modifyPrio (newScope result.final x y);
   cabal = callPackage ../build-support/cabal {
     enableLibraryProfiling = enableLibraryProfiling;
     enableCheckPhase = pkgs.stdenv.lib.versionOlder "7.4" self.ghc.ghcVersion;
+    glibcLocales = if pkgs.stdenv.isLinux then pkgs.glibcLocales else null;
   };
 
   # A variant of the cabal build driver that disables unit testing.