Disable CPU optimizations not supported by all x86_64 systems.

--- a/cmake/modules/SIMDExt.cmake	2017-03-23 22:22:58.254071694 +0100
+++ b/cmake/modules/SIMDExt.cmake	2017-03-23 22:23:22.446848845 +0100
@@ -5,11 +5,6 @@
 # HAVE_ARM_NEON
 # HAVE_INTEL_SSE
 # HAVE_INTEL_SSE2
-# HAVE_INTEL_SSE3
-# HAVE_INTEL_SSSE3
-# HAVE_INTEL_PCLMUL
-# HAVE_INTEL_SSE4_1
-# HAVE_INTEL_SSE4_2
 #
 # SIMD_COMPILE_FLAGS
 #
@@ -85,26 +80,6 @@
       if(HAVE_INTEL_SSE2)
         set(SIMD_COMPILE_FLAGS "${SIMD_COMPILE_FLAGS} -msse2")
       endif()
-      CHECK_C_COMPILER_FLAG(-msse3 HAVE_INTEL_SSE3)
-      if(HAVE_INTEL_SSE3)
-        set(SIMD_COMPILE_FLAGS "${SIMD_COMPILE_FLAGS} -msse3")
-      endif()
-      CHECK_C_COMPILER_FLAG(-mssse3 HAVE_INTEL_SSSE3)
-      if(HAVE_INTEL_SSSE3)
-        set(SIMD_COMPILE_FLAGS "${SIMD_COMPILE_FLAGS} -mssse3")
-      endif()
-      CHECK_C_COMPILER_FLAG(-mpclmul HAVE_INTEL_PCLMUL)
-      if(HAVE_INTEL_PCLMUL)
-        set(SIMD_COMPILE_FLAGS "${SIMD_COMPILE_FLAGS} -mpclmul")
-      endif()
-      CHECK_C_COMPILER_FLAG(-msse4.1 HAVE_INTEL_SSE4_1)
-      if(HAVE_INTEL_SSE4_1)
-        set(SIMD_COMPILE_FLAGS "${SIMD_COMPILE_FLAGS} -msse4.1")
-      endif()
-      CHECK_C_COMPILER_FLAG(-msse4.2 HAVE_INTEL_SSE4_2)
-      if(HAVE_INTEL_SSE4_2)
-        set(SIMD_COMPILE_FLAGS "${SIMD_COMPILE_FLAGS} -msse4.2")
-      endif()
     endif(CMAKE_SYSTEM_PROCESSOR MATCHES "amd64|x86_64|AMD64")
   endif(CMAKE_SYSTEM_PROCESSOR MATCHES "i686|amd64|x86_64|AMD64")
 elseif(CMAKE_SYSTEM_PROCESSOR MATCHES "(powerpc|ppc)64le")