going native (#7)

- Adds the -march=native flag when supported.

Author: lemire

CMakeLists.txt

@@ -5,7 +5,14 @@ set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_STANDARD_REQUIRED ON)
-
+include(CheckCXXCompilerFlag)
+unset(FASTPFOR_COMPILER_SUPPORTS_MARCH_NATIVE CACHE)
+CHECK_CXX_COMPILER_FLAG(-march=native FASTPFOR_COMPILER_SUPPORTS_MARCH_NATIVE)
+if(FASTPFOR_COMPILER_SUPPORTS_MARCH_NATIVE)
+    add_compile_options(-march=native)
+else()
+     message(STATUS "native target not supported")
+endif()
 if (NOT CMAKE_BUILD_TYPE)
   message(STATUS "No build type selected, default to Release")
   set(CMAKE_BUILD_TYPE Release CACHE STRING "Choose the type of build." FORCE)