+/// Predefined macros hell:
+///
+/// __GNUC__ Compiler is gcc, Clang or Intel on Linux
+/// __INTEL_COMPILER Compiler is Intel
+/// _MSC_VER Compiler is MSVC or Intel on Windows
+/// _WIN32 Building on Windows (any)
+/// _WIN64 Building on Windows 64 bit
+
+#if defined(_WIN64) && defined(_MSC_VER) // No Makefile used
+# include <intrin.h> // Microsoft header for _BitScanForward64()