Add support for database open with flags

Add support to:
  - BlockchainDB, BlockchainLMDB
  - blockchain_import utility to open LMDB database with one or more
    LMDB flags.

Sample use:
  $ blockchain_import --database lmdb#nosync
  $ blockchain_import --database lmdb#nosync,nometasync

3 files changed, 3 insertions, 4 deletions

diff --git a/src/blockchain_db/blockchain_db.h b/src/blockchain_db/blockchain_db.h
index d2b4a07a7..7b6b55a40 100644
--- a/src/blockchain_db/blockchain_db.h
+++ b/src/blockchain_db/blockchain_db.h
@@ -326,7 +326,7 @@ public:
   void show_stats();
 
   // open the db at location <filename>, or create it if there isn't one.
-  virtual void open(const std::string& filename) = 0;
+  virtual void open(const std::string& filename, const int db_flags = 0) = 0;
 
   // make sure implementation has a create function as well
   virtual void create(const std::string& filename) = 0;
diff --git a/src/blockchain_db/lmdb/db_lmdb.cpp b/src/blockchain_db/lmdb/db_lmdb.cpp
index 6d815c997..b1da6308f 100644
--- a/src/blockchain_db/lmdb/db_lmdb.cpp
+++ b/src/blockchain_db/lmdb/db_lmdb.cpp
@@ -635,9 +635,8 @@ BlockchainLMDB::BlockchainLMDB(bool batch_transactions)
   m_height = 0;
 }
 
-void BlockchainLMDB::open(const std::string& filename)
+void BlockchainLMDB::open(const std::string& filename, const int mdb_flags)
 {
-  int mdb_flags = 0;
   LOG_PRINT_L3("BlockchainLMDB::" << __func__);
 
   if (m_open)
diff --git a/src/blockchain_db/lmdb/db_lmdb.h b/src/blockchain_db/lmdb/db_lmdb.h
index 1a684548e..fa7cb988a 100644
--- a/src/blockchain_db/lmdb/db_lmdb.h
+++ b/src/blockchain_db/lmdb/db_lmdb.h
@@ -114,7 +114,7 @@ public:
   BlockchainLMDB(bool batch_transactions=false);
   ~BlockchainLMDB();
 
-  virtual void open(const std::string& filename);
+  virtual void open(const std::string& filename, const int mdb_flags=0);
 
   virtual void create(const std::string& filename);