Re-enable LLVM LTO on Neon targets.

dl/dl.gyp

 #  Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
 #
 #  Use of this source code is governed by a BSD-style license
 #  that can be found in the LICENSE 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.
 
 {
   'variables' : {
@@ skipping 269 matching lines @@
             'sp/src/arm/neon/armSP_FFT_CToC_FC32_Radix4_unsafe_s.S',
             'sp/src/arm/neon/armSP_FFT_CToC_FC32_Radix8_fs_unsafe_s.S',
             'sp/src/arm/neon/omxSP_FFTInv_CToC_FC32_Sfs_s.S',
             'sp/src/arm/neon/omxSP_FFTFwd_CToC_FC32_Sfs_s.S',
             # Real floating-point FFT
             'sp/src/arm/neon/armSP_FFTInv_CCSToR_F32_preTwiddleRadix2_unsafe_s.S',
             'sp/src/arm/neon/omxSP_FFTFwd_RToCCS_F32_Sfs_s.S',
             'sp/src/arm/neon/omxSP_FFTInv_CCSToR_F32_Sfs_s.S',
           ],
           'conditions': [
-            # Disable LTO due to NEON issues
+            # Disable GCC LTO due to NEON issues
             # crbug.com/408997
-            ['use_lto==1', {
+            ['clang==0 and use_lto==1', {
               'cflags!': [
                 '-flto',
                 '-ffat-lto-objects',
               ],
             }],
           ],
         },
       ],
     }],
   ],
 }