security: in key-chain.cpp for bind with _1, if using std::function, need namespace placeholders. Refs #1063.
diff --git a/src/security/key-chain.cpp b/src/security/key-chain.cpp
index 424a8e8..d3e7a6a 100644
--- a/src/security/key-chain.cpp
+++ b/src/security/key-chain.cpp
@@ -17,6 +17,10 @@
using namespace std;
using namespace ndn::ptr_lib;
+#if NDN_CPP_HAVE_STD_FUNCTION
+// In the std library, the placeholders are in a different namespace than boost.
+using namespace func_lib::placeholders;
+#endif
namespace ndn {