diff --git a/unsupported/Eigen/CXX11/Tensor b/unsupported/Eigen/CXX11/Tensor
index 05c5127a10..54d3cc18b0 100644
--- a/unsupported/Eigen/CXX11/Tensor
+++ b/unsupported/Eigen/CXX11/Tensor
@@ -34,6 +34,14 @@
 #include <random>
 #endif
 
+#ifdef _WIN32
+#include <winbase.h>
+#elif defined(__APPLE__)
+#include <mach/mach_time.h>
+#else
+#include <time.h>
+#endif
+
 #ifdef EIGEN_USE_THREADS
 #include <condition_variable>
 #include <deque>
diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h b/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h
index da9763a3da..1b031b7a1b 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorFunctors.h
@@ -196,7 +196,7 @@ int get_random_seed() {
     GetSystemTime(&st);
     return st.wSecond + 1000 * st.wMilliseconds;
 #elif defined __APPLE__
-    return mach_absolute_time();
+    return static_cast<int>(mach_absolute_time());
 #else
     timespec ts;
     clock_gettime(CLOCK_REALTIME, &ts);