Upstream support for giflib >= 5.1.

Upstream support for giflib >= 5.1.

DGifCloseFile now takes two arugments.  The second argument appears to be an
optional out-param with more information on failures.

( c.f. http://giflib.sourceforge.net/gif_lib.html )

PS 1 is the original patch we received from google3.  I've updated it a bit to
be pedantically legal C++98.

BUG=skia:

Committed: https://skia.googlesource.com/skia/+/59c69479d44242350b303714a2cec8764c7f11a3

[mtklein, 2015-01-20 18:49:45]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-01-20 18:49:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/860853003/1

[commit-bot: I haz the power, 2015-01-20 18:49:52]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-01-21 00:49 UTC

[commit-bot: I haz the power, 2015-01-20 18:51:01]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2015-01-20 18:51:02]

Try jobs failed on following builders:
  Test-Ubuntu13.10-GCE-NoGPU-x86_64-Debug-Trybot on client.skia
(http://build.chromium.org/p/client.skia/builders/Test-Ubuntu13.10-GCE-NoGPU-x...)
  Test-Ubuntu13.10-GCE-NoGPU-x86_64-Release-Shared-Trybot on client.skia
(http://build.chromium.org/p/client.skia/builders/Test-Ubuntu13.10-GCE-NoGPU-x...)
  Build-Ubuntu13.10-GCC4.8-Arm7-Debug-Android-Trybot on client.skia.compile
(http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu13.10-GC...)
  Build-Ubuntu13.10-GCC4.8-x86_64-Release-Trybot on client.skia.compile
(http://build.chromium.org/p/client.skia.compile/builders/Build-Ubuntu13.10-GC...)

[mtklein, 2015-01-20 18:53:19]

The CQ bit was checked by mtklein@google.com

[commit-bot: I haz the power, 2015-01-20 18:53:51]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/860853003/20001

[commit-bot: I haz the power, 2015-01-20 18:53:52]

Note for Reviewers:
The CQ is waiting for an approval.
If you believe that the CL is not ready yet, or if you would like to L-G-T-M
with comments then please uncheck the CQ checkbox.

Waiting for LGTM from valid reviewer(s) till 2015-01-21 00:53 UTC

[mtklein_C, 2015-01-20 19:02:17]

mtklein@chromium.org changed reviewers:
+ scroggo@google.com
- mtklein@google.com

[scroggo, 2015-01-20 20:37:49]

LGTM

FYI: If you want a Skia bug to attach, it's

BUG=skia:2776

[commit-bot: I haz the power, 2015-01-20 20:38:09]

Committed patchset #2 (id:20001) as
https://skia.googlesource.com/skia/+/59c69479d44242350b303714a2cec8764c7f11a3

[mtklein, 2015-01-20 20:40:34]

On 2015/01/20 20:37:49, scroggo wrote:
> LGTM
> 
> FYI: If you want a Skia bug to attach, it's
> 
> BUG=skia:2776

Ooh, nice!