Small compilation fixes for GCC 6.3 (apache#470)

Author: merlimat

pulsar-client-cpp/lib/ObjectPool.h

@@ -152,6 +152,7 @@ class Allocator {
     };
 
     static boost::thread_specific_ptr<Impl> implPtr_;
+    typedef T value_type;
     typedef size_t size_type;
     typedef T* pointer;
     typedef const void* const_pointer;

pulsar-client-cpp/lib/SharedBuffer.h

@@ -17,6 +17,7 @@
 #ifndef LIB_SHARED_BUFFER_H_
 #define LIB_SHARED_BUFFER_H_
 
+#include <boost/array.hpp>
 #include <boost/asio.hpp>
 #include <boost/make_shared.hpp>
 #include <boost/shared_ptr.hpp>

pulsar-client-cpp/tests/ConsumerStatsTest.cc

@@ -45,7 +45,7 @@ void partitionedCallbackFunction(Result result, BrokerConsumerStats brokerConsum
     latch.countdown();
 }
 
-void simpleCallbackFunction(Result result, BrokerConsumerStats& brokerConsumerStats, Result expectedResult,
+void simpleCallbackFunction(Result result, BrokerConsumerStats brokerConsumerStats, Result expectedResult,
                             uint64_t expectedBacklog, ConsumerType expectedConsumerType) {
     LOG_DEBUG(brokerConsumerStats);
     ASSERT_EQ(result, expectedResult);