Removing warnings from Windows Ninja configuration

Windows Ninja build was complaining about /W4 and /W3 being
specified, and C++ latest and C++ 17.  This fixs those complaints.

Author: mjp41

CMakeLists.txt

@@ -26,7 +26,13 @@ macro(linklibs project)
 endmacro()
 
 if(MSVC)
-  add_compile_options(/WX /W4 /wd4127 /wd4324 /wd4201 /std:c++latest)
+  # Force to always compile with W4
+  if(CMAKE_CXX_FLAGS MATCHES "/W[0-4]")
+    string(REGEX REPLACE "/W[0-4]" "/W4" CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}")
+  else()
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
+  endif()
+  add_compile_options(/WX /wd4127 /wd4324 /wd4201)
   set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} /Zi")
   set(CMAKE_EXE_LINKER_FLAGS_RELEASE "${CMAKE_EXE_LINKER_FLAGS_RELEASE} /DEBUG")
 else()