Fix build when Vc is disabled.

CMakeLists.txt

@@ -105,8 +105,10 @@ set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lpthread")
 SET(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} ${INCLUDES} -W -O3 -DNDEBUG")
 SET(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS}" )
 
-include(VcMacros)
-vc_set_preferred_compiler_flags()
+if(ENABLE_VC)
+  include(VcMacros)
+  vc_set_preferred_compiler_flags()
+endif()
 
 if (USE_AVX2)
   include_directories(${Vc_INCLUDE_DIR})

lib/generate/config.h.in

 #pragma once
 
-#cmakedefine01 USE_AVX2 @USE_AVX2@
+#cmakedefine USE_AVX2 @USE_AVX2@