skip neon code in libwebp when neon is explicitly unavailable

third_party/libwebp/dsp/dec.c

 // Copyright 2010 Google Inc. All Rights Reserved.
 //
 // Use of this source code is governed by a BSD-style license
 // that can be found in the COPYING file in the root of the source
 // tree. An additional intellectual property rights grant can be found
 // in the file PATENTS. All contributing project authors may
 // be found in the AUTHORS file in the root of the source tree.
 // -----------------------------------------------------------------------------
 //
 // Speed-critical decoding functions.
@@ skipping 679 matching lines @@
 VP8LumaFilterFunc VP8VFilter16i;
 VP8LumaFilterFunc VP8HFilter16i;
 VP8ChromaFilterFunc VP8VFilter8i;
 VP8ChromaFilterFunc VP8HFilter8i;
 VP8SimpleFilterFunc VP8SimpleVFilter16;
 VP8SimpleFilterFunc VP8SimpleHFilter16;
 VP8SimpleFilterFunc VP8SimpleVFilter16i;
 VP8SimpleFilterFunc VP8SimpleHFilter16i;
 
 extern void VP8DspInitSSE2(void);
+#if defined(WEBP_USE_NEON)
 extern void VP8DspInitNEON(void);
+#endif
 
 void VP8DspInit(void) {
   DspInitTables();
 
   VP8Transform = TransformTwo;
   VP8TransformUV = TransformUV;
   VP8TransformDC = TransformDC;
   VP8TransformDCUV = TransformDCUV;
 
   VP8VFilter16 = VFilter16;
@@ skipping 19 matching lines @@
     if (VP8GetCPUInfo(kNEON)) {
       VP8DspInitNEON();
     }
 #endif
   }
 }
 
 #if defined(__cplusplus) || defined(c_plusplus)
 }    // extern "C"
 #endif