Fixed redundant SSE flag in 64bit mode.

CMakeLists.txt

@@ -82,7 +82,8 @@ if (MSVC)
     set (CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} /MTd")
     set (CMAKE_CXX_FLAGS_RELWITHDEBINFO "${CMAKE_CXX_FLAGS_RELEASE} /MT /fp:fast /Zi /GS- /D _SECURE_SCL=0")
     set (CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELWITHDEBINFO}")
-    if (ENABLE_SSE)
+    # SSE flag is redundant if already compiling as 64bit
+    if (ENABLE_SSE AND NOT ENABLE_64BIT)
         set (CMAKE_C_FLAGS "${CMAKE_C_FLAGS} /arch:SSE")
         set (CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /arch:SSE")
     endif ()