Apple devices do not support CRC32 instructions. Don't believe Clang's lies.

src/core/SkOpts.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkCpu.h"
 #include "SkHalf.h"
 #include "SkOnce.h"
 #include "SkOpts.h"
 
 #if defined(SK_ARM_HAS_NEON)
-    #if defined(__ARM_FEATURE_CRC32)
+    #if defined(SK_ARM_HAS_CRC32)
         #define SK_OPTS_NS neon_and_crc32
     #else
         #define SK_OPTS_NS neon
     #endif
 #elif SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_AVX2
     #define SK_OPTS_NS avx2
 #elif SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_AVX
     #define SK_OPTS_NS avx
 #elif SK_CPU_SSE_LEVEL >= SK_CPU_SSE_LEVEL_SSE42
     #define SK_OPTS_NS sse42
@@ skipping 86 matching lines @@
 
     #endif
 #endif
     }
 
     void Init() {
         static SkOnce once;
         once(init);
     }
 }  // namespace SkOpts