remove "using namespace std" from headers

It's nasty, and actually breaks on Solaris, where if.h fails to
build due to:

  struct map *if_memmap;

4 files changed, 8 insertions, 2 deletions

diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 4e1ab8a48..3d586a704 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -61,6 +61,8 @@
 
 #define FIND_BLOCKCHAIN_SUPPLEMENT_MAX_SIZE (100*1024*1024) // 100 MB
 
+using namespace crypto;
+
 //#include "serialization/json_archive.h"
 
 /* TODO:
diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index 3f56ffac7..a10692dad 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -498,8 +498,8 @@ namespace cryptonote
       return false;
     }
 
-    tx_hash = null_hash;
-    tx_prefixt_hash = null_hash;
+    tx_hash = crypto::null_hash;
+    tx_prefixt_hash = crypto::null_hash;
 
     if(!parse_tx_from_blob(tx, tx_hash, tx_prefixt_hash, tx_blob))
     {
diff --git a/src/cryptonote_core/cryptonote_tx_utils.cpp b/src/cryptonote_core/cryptonote_tx_utils.cpp
index 9409a60a5..feefc1592 100644
--- a/src/cryptonote_core/cryptonote_tx_utils.cpp
+++ b/src/cryptonote_core/cryptonote_tx_utils.cpp
@@ -40,6 +40,8 @@ using namespace epee;
 #include "crypto/hash.h"
 #include "ringct/rctSigs.h"
 
+using namespace crypto;
+
 namespace cryptonote
 {
   //---------------------------------------------------------------
diff --git a/src/cryptonote_core/tx_pool.cpp b/src/cryptonote_core/tx_pool.cpp
index 6bfcfe529..e6f217463 100644
--- a/src/cryptonote_core/tx_pool.cpp
+++ b/src/cryptonote_core/tx_pool.cpp
@@ -51,6 +51,8 @@
 
 DISABLE_VS_WARNINGS(4244 4345 4503) //'boost::foreach_detail_::or_' : decorated name length exceeded, name was truncated
 
+using namespace crypto;
+
 namespace cryptonote
 {
   namespace