Android's Clang toolchain can't assemble the JPEG's .S files.

platform_tools/android/gyp/dependencies.gypi

 # Copyright 2015 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 # This GYP file stores the dependencies necessary to build Skia on the Android
 # platform. The OS doesn't provide many stable libraries as part of the
 # distribution so we have to build a few of them ourselves.
 #
 # NOTE: We tried adding the gyp file to the android/ directory at the root of
@@ skipping 133 matching lines @@
         '../third_party/externals/jpeg/jidctfst.c',
         '../third_party/externals/jpeg/jidctint.c',
         '../third_party/externals/jpeg/jidctred.c',
         '../third_party/externals/jpeg/jmem-android.c',
         '../third_party/externals/jpeg/jmemmgr.c',
         '../third_party/externals/jpeg/jquant1.c',
         '../third_party/externals/jpeg/jquant2.c',
         '../third_party/externals/jpeg/jutils.c',
       ],
       'conditions': [
-        [ 'arm_neon == 1',
+        [ 'arm_neon == 1 and skia_clang_build == 0',
           {
             'sources' : [
               '../third_party/externals/jpeg/armv6_idct.S',
               '../third_party/externals/jpeg/jsimd_arm_neon.S',
               '../third_party/externals/jpeg/jsimd_neon.c',
             ],
             'defines' : [
               'NV_ARM_NEON',
             ],
           },
@@ skipping 89 matching lines @@
           }],
         ],
         'sources': [
           '../app/jni/com_skia_SkiaSampleRenderer.cpp',
         ],
       },
 
     },
   ]
 }