Update giflib to 5.1.1 (AOSP hash)

gyp/giflib.gyp

 # Copyright 2014 Google Inc.
 #
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'variables': {
     'skia_warnings_as_errors': 0,
   },
   'targets': [
@@ skipping 17 matching lines @@
               '-w',
             ],
             'xcode_settings': {
               'WARNING_CFLAGS': [
                 '-w'
               ],
             },
             'msvs_settings': {
               'VCCLCompilerTool': {
                 'AdditionalOptions': [
-                  '/w',
+                  '/wd4996',
+                  '/wd4018',
+                  '/wd4267',
                 ],
               },
             },
             'sources': [
               '../third_party/externals/giflib/dgif_lib.c',
               '../third_party/externals/giflib/gifalloc.c',
               '../third_party/externals/giflib/gif_err.c',
             ],
             'conditions' : [
               [ 'skia_os == "win"', {
@@ skipping 13 matching lines @@
               'include_dirs': [
                 'external/giflib',
               ]
             }
           }
         ]
       ]
     }
   ]
 }