Merge remote-tracking branch 'takt/sierra-haskell'

pkgs/development/haskell-modules/generic-builder.nix

···
         configureFlags+=" --extra-lib-dirs=$p/lib"
       fi
     done
+  '' + (optionalString stdenv.isDarwin ''
+    # Work around a limit in the Mac OS X Sierra linker on the number of paths
+    # referenced by any one dynamic library:
+    #
+    # Create a local directory with symlinks of the *.dylib (Mac OS X shared
+    # libraries) from all the dependencies.
+    local dynamicLinksDir="$out/lib/links"
+    mkdir -p $dynamicLinksDir
+    local foundDylib=false
+    for d in $(grep dynamic-library-dirs $packageConfDir/*|awk '{print $2}'); do
+      ln -s $d/*.dylib $dynamicLinksDir
+    done
+    # Edit the local package DB to reference the links directory.
+    for f in $packageConfDir/*.conf; do
+      sed -i "s,dynamic-library-dirs: .*,dynamic-library-dirs: $dynamicLinksDir," $f
+    done
+  '') + ''
     ${ghcCommand}-pkg --${packageDbFlag}="$packageConfDir" recache
 
     runHook postSetupCompilerEnvironment

pkgs/development/haskell-modules/with-packages-wrapper.nix

···
         makeWrapper ${ghc}/bin/$prg $out/bin/$prg --add-flags "${packageDBFlag}=${packageCfgDir}"
       fi
     done
-
+  '' + (lib.optionalString stdenv.isDarwin ''
+    # Work around a linker limit in Mac OS X Sierra (see generic-builder.nix):
+    local packageConfDir="$out/lib/${ghc.name}/package.conf.d";
+    local dynamicLinksDir="$out/lib/links"
+    mkdir -p $dynamicLinksDir
+    # Clean up the old links that may have been (transitively) included by
+    # symlinkJoin:
+    rm -f $dynamicLinksDir/*
+    for d in $(grep dynamic-library-dirs $packageConfDir/*|awk '{print $2}'); do
+      ln -s $d/*.dylib $dynamicLinksDir
+    done
+    for f in $packageConfDir/*.conf; do
+      # Initially, $f is a symlink to a read-only file in one of the inputs
+      # (as a result of this symlinkJoin derivation).
+      # Replace it with a copy whose dynamic-library-dirs points to
+      # $dynamicLinksDir
+      cp $f $f-tmp
+      rm $f
+      sed "s,dynamic-library-dirs: .*,dynamic-library-dirs: $dynamicLinksDir," $f-tmp > $f
+      rm $f-tmp
+    done
+  '') + ''
     ${lib.optionalString hasLibraries "$out/bin/${ghcCommand}-pkg recache"}
     ${# ghcjs will read the ghc_libdir file when resolving plugins.
       lib.optionalString (isGhcjs && ghcLibdir != null) ''