openssl: Use Darwin patch for cross-builds too.

Might be better to have something like stdenv.isDarwinTarget, which can
be used to test for native Darwin _and_ cross-built Darwin as a target.

Signed-off-by: aszlig <aszlig@redmoonstudios.org>

pkgs/development/libraries/openssl/default.nix

@@ -8,7 +8,9 @@ let
     (throw "openssl needs its platform name cross building" null)
     stdenv.cross;
 
-  patchesCross = isCross:
+  patchesCross = isCross: let
+    isDarwin = stdenv.isDarwin || (isCross && stdenv.cross.libc == "libSystem");
+  in
     [ # Allow the location of the X509 certificate file (the CA
       # bundle) to be set through the environment variable
       # ‘OPENSSL_X509_CERT_FILE’.  This is necessary because the
@@ -29,7 +31,7 @@ let
           ./kfreebsd-gnu.patch
         ]
 
-    ++ stdenv.lib.optional stdenv.isDarwin ./darwin-arch.patch;
+    ++ stdenv.lib.optional isDarwin ./darwin-arch.patch;
 
 in