add chrono in more places

Extractor/ExtractionContainers.cpp

@@ -36,6 +36,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include <stxxl/sort>
 
+#include <chrono>
+
 ExtractionContainers::ExtractionContainers() {
     //Check if stxxl can be instantiated
     stxxl::vector<unsigned> dummy_vector;

Tools/io-benchmark.cpp

@@ -40,7 +40,9 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 #ifdef __linux__
 #include <malloc.h>
 #endif
+
 #include <algorithm>
+#include <chrono>
 #include <iomanip>
 #include <numeric>
 #include <vector>