I wish this worked

pkgs/development/libraries/libuv/default.nix

@@ -1,5 +1,5 @@
 { stdenv, lib, fetchFromGitHub, autoconf, automake, libtool, pkgconfig
-, ApplicationServices, CoreServices }:
+, ApplicationServices, CoreServices, targetPlatform, buildPlatform }:
 
 stdenv.mkDerivation rec {
   version = "1.11.0";
@@ -37,7 +37,7 @@ stdenv.mkDerivation rec {
   # These should be turned back on, but see https://github.com/NixOS/nixpkgs/issues/23651
   # For now the tests are just breaking large swaths of the nixpkgs binary cache for Darwin,
   # and I'd rather have everything else work at all than have stronger assurance here.
-  doCheck = !stdenv.isDarwin;
+  doCheck = !(stdenv.isDarwin /*|| (targetPlatform != buildPlatform)*/);
 
   meta = with lib; {
     description = "A multi-platform support library with a focus on asynchronous I/O";

pkgs/os-specific/darwin/binutils/default.nix

@@ -35,6 +35,9 @@ stdenv.mkDerivation {
     for i in ${stdenv.lib.concatStringsSep " " (builtins.map (e: prefix + e) cmds)}; do
       ln -sf "${cctools}/bin/$i" "$out/bin/$i"
     done
+    for i in dsymutil; do
+      ln -sf "${cctools}/bin/$i" "$out/bin/$i"
+    done
 
     for i in ${binutils-raw.dev or binutils-raw.out}/include/*.h; do
       ln -s "$i" "$out/include/$(basename $i)"

pkgs/os-specific/darwin/cctools/port.nix

@@ -60,6 +60,9 @@ let
       substituteInPlace cctools/include/Makefile \
         --replace "/bin/" ""
 
+      substituteInPlace cctools/as/driver.c \
+        --replace 'if(arch_name == NULL){' 'if (arch_name == NULL) {arch_name = "x86_64";} if(arch_name == NULL){'
+
       patchShebangs tools
       sed -i -e 's/which/type -P/' tools/*.sh
 
@@ -99,8 +102,11 @@ let
         chmod +x $out/bin/dsymutil
       ''
       else ''
+        . ${makeWrapper}/nix-support/setup-hook
+        wrapProgram "$out/bin/${targetPlatform.config}-as" \
+          --suffix PATH : ${stdenv.lib.makeBinPath [ clang ]}
         for tool in dyldinfo dwarfdump dsymutil; do
-          ${makeWrapper}/bin/makeWrapper "${maloader}/bin/ld-mac" "$out/bin/${targetPlatform.config}-$tool" \
+          makeWrapper "${maloader}/bin/ld-mac" "$out/bin/${targetPlatform.config}-$tool" \
             --add-flags "${xctoolchain}/bin/$tool"
           ln -s "$out/bin/${targetPlatform.config}-$tool" "$out/bin/$tool"
         done

pkgs/os-specific/darwin/maloader/default.nix

@@ -1,23 +1,26 @@
-{ stdenv, fetchgit, opencflite, clang, libcxx }:
+{ stdenv, fetchgit, opencflite, clang, libcxx, libcxxabi }:
 
 stdenv.mkDerivation {
   name = "maloader-0git";
 
   src = fetchgit {
     url = "git://github.com/shinh/maloader.git";
     rev = "5f220393e0b7b9ad0cf1aba0e89df2b42a1f0442";
-    sha256 = "07j9b7n0grrbxxyn2h8pnk6pa8b370wq5z5zwbds8dlhi7q37rhn";
+    sha256 = "0dd1pn07x1y8pyn5wz8qcl1c1xwghyya4d060m3y9vx5dhv9xmzw";
   };
 
   postPatch = ''
     sed -i \
       -e '/if.*loadLibMac.*mypath/s|mypath|"'"$out/lib/"'"|' \
       -e 's|libCoreFoundation\.so|${opencflite}/lib/&|' \
       ld-mac.cc
+    substituteInPlace Makefile \
+      --replace "-Werror" "" \
+      ;
   '';
 
   NIX_CFLAGS_COMPILE = "-I${libcxx}/include/c++/v1";
-  buildInputs = [ clang libcxx ];
+  buildInputs = [ clang libcxx libcxxabi ];
   buildFlags = [ "USE_LIBCXX=1" "release" ];
 
   installPhase = ''

pkgs/os-specific/darwin/opencflite/default.nix

@@ -1,5 +1,5 @@
-{ stdenv, fetchurl, icu, libuuid, tzdata }:
-
+{ stdenv, fetchurl, icu, libuuid, tzdata, utillinux, clang }:
+let libuuid = (utillinux.override { systemd = null; }).dev; in
 stdenv.mkDerivation rec {
   name = "opencflite-${version}";
   version = "476.19.0";

pkgs/os-specific/darwin/xcode/default.nix

@@ -4,6 +4,10 @@ with stdenv.lib;
 
 let
   osxVersion = "10.9";
+  # this path comes from a manual install of an older version, because the current one segfaults
+  # nix-env -iA xpwn
+  # readlink `type -P xpwntool`
+  xpwn = "/nix/store/xj6bcqgn7wxidnj08yrmdbbhzr57lfc9-xpwn-0.5.8git";
 in stdenv.mkDerivation rec {
   name = "xcode-${version}";
   version = "5.1";