Don't compile ldb tool into static library

Summary:
This is first step of my effort to reduce size of librocksdb.a for use in mobile.

ldb object files are huge and are ment to be used as a command line tool. I moved them to `tools/` directory and include them only when compiling `ldb`

This diff reduced librocksdb.a from 42MB to 39MB on my mac (not stripped).

Test Plan: ran ldb

Reviewers: dhruba, haobo, sdong, ljin, yhchiang

Reviewed By: yhchiang

CC: leveldb

Differential Revision: https://reviews.facebook.net/D17823

Makefile

@@ -113,6 +113,10 @@ TOOLS = \
 	db_repl_stress \
 	blob_store_bench
 
+LDB_OBJECTS = \
+		tools/ldb_cmd.o \
+		tools/ldb_tool.o
+
 
 PROGRAMS = db_bench signal_test table_reader_bench $(TESTS) $(TOOLS)
 BENCHMARKS = db_bench_sqlite3 db_bench_tree_db table_reader_bench
@@ -410,8 +414,8 @@ auto_roll_logger_test: util/auto_roll_logger_test.o $(LIBOBJECTS) $(TESTHARNESS)
 sst_dump: tools/sst_dump.o $(LIBOBJECTS)
 	$(CXX) tools/sst_dump.o $(LIBOBJECTS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
 
-ldb: tools/ldb.o $(LIBOBJECTS)
-	$(CXX) tools/ldb.o $(LIBOBJECTS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
+ldb: tools/ldb.o $(LDB_OBJECTS) $(LIBOBJECTS)
+	$(CXX) tools/ldb.o $(LDB_OBJECTS) $(LIBOBJECTS) $(EXEC_LDFLAGS) -o $@ $(LDFLAGS) $(COVERAGEFLAGS)
 
 # ---------------------------------------------------------------------------
 # Jni stuff

tools/ldb.cc

@@ -4,7 +4,7 @@
 //  of patent rights can be found in the PATENTS file in the same directory.
 //
 
-#include "rocksdb/ldb_tool.h"
+#include "tools/ldb_tool.h"
 
 int main(int argc, char** argv) {
   rocksdb::LDBTool tool;

tools/ldb_cmd.cc

@@ -3,7 +3,7 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.
 //
-#include "util/ldb_cmd.h"
+#include "tools/ldb_cmd.h"
 
 #include "db/dbformat.h"
 #include "db/db_impl.h"

tools/ldb_cmd.h

@@ -17,7 +17,7 @@
 #include "rocksdb/iterator.h"
 #include "rocksdb/slice.h"
 #include "util/logging.h"
-#include "util/ldb_cmd_execute_result.h"
+#include "tools/ldb_cmd_execute_result.h"
 #include "util/string_util.h"
 #include "utilities/utility_db.h"
 #include "utilities/ttl/db_ttl.h"

tools/ldb_tool.cc

@@ -3,8 +3,8 @@
 //  LICENSE file in the root directory of this source tree. An additional grant
 //  of patent rights can be found in the PATENTS file in the same directory.
 //
-#include "rocksdb/ldb_tool.h"
-#include "util/ldb_cmd.h"
+#include "tools/ldb_tool.h"
+#include "tools/ldb_cmd.h"
 
 namespace rocksdb {
 

tools/ldb_tool.h

@@ -2,8 +2,8 @@
 // This source code is licensed under the BSD-style license found in the
 // LICENSE file in the root directory of this source tree. An additional grant
 // of patent rights can be found in the PATENTS file in the same directory.
-#ifndef STORAGE_ROCKSDB_INCLUDE_LDB_TOOL_H
-#define STORAGE_ROCKSDB_INCLUDE_LDB_TOOL_H
+#pragma once
+
 #include "rocksdb/options.h"
 
 namespace rocksdb {
@@ -14,5 +14,3 @@ class LDBTool {
 };
 
 } // namespace rocksdb
-
-#endif // STORAGE_ROCKSDB_INCLUDE_LDB_TOOL_H