Everyone gets a namespace {}.

src/opts/SkNx_sse.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 SkNx_sse_DEFINED
 #define SkNx_sse_DEFINED
 
 // This file may assume <= SSE2, but must check SK_CPU_SSE_LEVEL for anything more recent.
-#include <immintrin.h>
+
+namespace {  // See SkNx.h
 
 template <>
 class SkNb<2, 4> {
 public:
     SkNb(const __m128i& vec) : fVec(vec) {}
 
     SkNb() {}
     bool allTrue() const { return 0xff == (_mm_movemask_epi8(fVec) & 0xff); }
     bool anyTrue() const { return 0x00 != (_mm_movemask_epi8(fVec) & 0xff); }
 
@@ skipping 297 matching lines @@
     template <int k> uint8_t kth() const {
         SkASSERT(0 <= k && k < 16);
         // SSE4.1 would just `return _mm_extract_epi8(fVec, k)`.  We have to read 16-bits instead.
         int pair = _mm_extract_epi16(fVec, k/2);
         return k % 2 == 0 ? pair : (pair >> 8);
     }
 
     __m128i fVec;
 };
 
+}  // namespace
+
 #endif//SkNx_sse_DEFINED