Re-enable LLVM LTO on Neon targets.

LTO was disabled due to a GCC compiler bug that does not affect LLVM.
This fixes the build in the cfi_vptr==1 configuration, which requires LLVM LTO.

R=pcc@google.com
BUG=chromium:469376

Review URL: https://webrtc-codereview.appspot.com/57659004.

README.chromium

 Name: libyuv
 URL: http://code.google.com/p/libyuv/
-Version: 1467
+Version: 1469
 License: BSD
 License File: LICENSE
 

include/libyuv/version.h

@@ -11,6 +11,6 @@
 #ifndef INCLUDE_LIBYUV_VERSION_H_  // NOLINT
 #define INCLUDE_LIBYUV_VERSION_H_
 
-#define LIBYUV_VERSION 1467
+#define LIBYUV_VERSION 1469
 
 #endif  // INCLUDE_LIBYUV_VERSION_H_  NOLINT

libyuv.gyp

@@ -50,7 +50,7 @@
           ],
           'conditions': [
             # Disable LTO in libyuv_neon target due to gcc 4.9 compiler bug.
-            ['use_lto == 1', {
+            ['clang == 0 and use_lto == 1', {
               'cflags!': [
                 '-flto',
                 '-ffat-lto-objects',