Fix the setting of simd flags in cmake when there is no avx and sse3 support.

cmake/configure.cmake

@@ -33,11 +33,11 @@ if(NOT WITH_PROFILER)
 endif(NOT WITH_PROFILER)
 
 if(NOT CMAKE_CROSSCOMPILING)
-    if(WITH_AVX)
+    if(WITH_AVX AND AVX_FOUND)
         set(SIMD_FLAG ${AVX_FLAG})
-    else(WITH_AVX)
+    elseif(SSE3_FOUND)
         set(SIMD_FLAG ${SSE3_FLAG})
-    endif(WITH_AVX)
+    endif()
 endif()
 
 if(NOT WITH_GPU)