Added support building on MSVC toolkit ClangCL

More info in answer: https://stackoverflow.com/questions/49480535/how-to-differentiate-between-clang-and-clang-cl

CMakeLists.txt

@@ -9,9 +9,17 @@ PROJECT(${NAME})
 ENABLE_TESTING()
 
 # Update if necessary
-SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")
-SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
-SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3")
+IF(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  IF("${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /std:c++17")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /O2")
+    SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /O2")
+  else()
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")
+    SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -O3")
+    SET(CMAKE_C_FLAGS "${CMAKE_C_FLAGS} -O3")
+  endif()
+endif()
 
 # BUILD AND INCLUDE GOOGLETEST
 ADD_SUBDIRECTORY(libs/googletest/)