https://bugs.gentoo.org/422577

 error: 'usleep' was not declared in this scope

 
 Benchmark.cpp | 1 +
 main.cpp      | 1 +
 2 files changed, 2 insertions(+)

--- a/Benchmark.cpp
+++ b/Benchmark.cpp
@@ -18,6 +18,7 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.               *
  ***************************************************************************/
 #include <cstring>
+#include <unistd.h>
 #include "Benchmark.hpp"
 #include "Stopwatch.hpp"
 #include "Main.hpp"
--- a/main.cpp
+++ b/main.cpp
@@ -20,6 +20,7 @@
 
 #include <sstream>
 #include <cstring>
+#include <unistd.h>
 using std::stringstream;