make: Conditionally link to the OSX Security framework.
diff --git a/ndn-cpp/security/identity/osx-private-key-storage.cpp b/ndn-cpp/security/identity/osx-private-key-storage.cpp
index d1ea2c5..2a58d85 100644
--- a/ndn-cpp/security/identity/osx-private-key-storage.cpp
+++ b/ndn-cpp/security/identity/osx-private-key-storage.cpp
@@ -5,10 +5,9 @@
  * See COPYING for copyright and distribution information.
  */
 
-// Only compile if ndn-cpp-config.h defines NDN_CPP_HAVE_OSX_SECKEYCHAIN 1.
+// Only compile if ndn-cpp-config.h defines NDN_CPP_HAVE_OSX_SECURITY 1.
 #include "../../ndn-cpp-config.h"
-#if 0 // temporarily disable.
-//#if NDN_CPP_HAVE_OSX_SECKEYCHAIN
+#if NDN_CPP_HAVE_OSX_SECURITY
 
 #include <fstream>
 #include <sstream>
@@ -513,4 +512,4 @@
   
 }
 
-#endif NDN_CPP_HAVE_OSX_SECKEYCHAIN
+#endif NDN_CPP_HAVE_OSX_SECURITY