Guard SIMD code with !defined(SKNX_NO_SIMD).

src/core/Sk2x.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef Sk2x_DEFINED
 #define Sk2x_DEFINED
 
 #include "SkTypes.h"
+#include "SkNx.h"
 
 #define SK2X_PREAMBLE 1
-    #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
+    #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2 && !defined(SKNX_NO_SIMD)
         #include "../opts/Sk2x_sse.h"
-    #elif defined(__ARM_NEON__)
+    #elif defined(__ARM_NEON__)                   && !defined(SKNX_NO_SIMD)
         #include "../opts/Sk2x_neon.h"
     #else
         #include "../opts/Sk2x_none.h"
     #endif
 #undef SK2X_PREAMBLE
 
 template <typename T> class Sk2x;
 typedef Sk2x<float>  Sk2f;
 typedef Sk2x<double> Sk2d;
 
@@ skipping 31 matching lines @@
     Sk2x& operator *=(const Sk2x& o) { return (*this = *this * o); }
 
     Sk2x rsqrt() const;   // Approximate 1/this->sqrt().
     Sk2x  sqrt() const;   // this->multiply(this->rsqrt()) may be faster, but less precise.
 
     static Sk2x Min(const Sk2x&, const Sk2x&);
     static Sk2x Max(const Sk2x&, const Sk2x&);
 
 private:
 #define SK2X_PRIVATE 1
-    #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
+    #if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2 && !defined(SKNX_NO_SIMD)
         #include "../opts/Sk2x_sse.h"
-    #elif defined(__ARM_NEON__)
+    #elif defined(__ARM_NEON__)                   && !defined(SKNX_NO_SIMD)
         #include "../opts/Sk2x_neon.h"
     #else
         #include "../opts/Sk2x_none.h"
     #endif
 #undef SK2X_PRIVATE
 };
 
-#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2
+#if SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE2 && !defined(SKNX_NO_SIMD)
     #include "../opts/Sk2x_sse.h"
-#elif defined(__ARM_NEON__)
+#elif defined(__ARM_NEON__)                   && !defined(SKNX_NO_SIMD)
     #include "../opts/Sk2x_neon.h"
 #else
     #include "../opts/Sk2x_none.h"
 #endif
 
 #endif//Sk2x_DEFINED