darwin cross: include CoreFoundation in stdenv

pkgs/stdenv/cross/default.nix

···
       # Prior overrides are surely not valid as packages built with this run on
       # a different platform, and so are disabled.
       overrides = _: _: {};
-      extraBuildInputs = [ ]; # Old ones run on wrong platform
+      extraBuildInputs = [ ] # Old ones run on wrong platform
+         ++ lib.optionals hostPlatform.isDarwin [ buildPackages.targetPackages.darwin.apple_sdk.frameworks.CoreFoundation ]
+         ;
       allowedRequisites = null;
 
       hasCC = !targetPlatform.isGhcjs;

pkgs/top-level/all-packages.nix

···
   # just the plain stdenv.
   stdenv_32bit = lowPrio (if stdenv.hostPlatform.is32bit then stdenv else multiStdenv);
 
-  stdenvNoCC = stdenv.override { cc = null; hasCC = false; };
+  stdenvNoCC = stdenv.override (
+    { cc = null; hasCC = false; }
+
+    // lib.optionalAttrs (stdenv.hostPlatform.isDarwin && (stdenv.hostPlatform != stdenv.buildPlatform)) {
+      # TODO: This is a hack to use stdenvNoCC to produce a CF when cross
+      # compiling. It's not very sound. The cross stdenv has:
+      #   extraBuildInputs = [ targetPackages.darwin.apple_sdks.frameworks.CoreFoundation ]
+      # and uses stdenvNoCC. In order to make this not infinitely recursive, we need to exclude
+      # this extraBuildInput.
+      extraBuildInputs = [];
+    }
+  );
 
   mkStdenvNoLibs = stdenv: let
     bintools = stdenv.cc.bintools.override {