Add default variable 'use_system_yasm%': 0

Add default variable 'use_system_yasm%': 0

When compiling for NaCL the following build error

native_client/build/gyp_nacl all.gyp -Dgtest_target_type=executable -Dmsan=0
Updating projects from gyp files...
gyp: name 'use_system_yasm' is not defined while evaluating condition
'use_system_yasm==1' in chromium/src/third_party/libjpeg_turbo/libjpeg.gyp

Adding use_system_yasm=0 to the command line works. (use_system_yasm=1 does not work).
Adding a default to the gyp file allows the build to work without specifying the
default value for this variable.

BUG=None
TESTED=native_client/build/gyp_nacl all.gyp -Dgtest_target_type=executable -Dmsan=0 -Duse_system_yasm=0
R=kjellander@chromium.org, noel@chromium.org

Committed: https://chromium.googlesource.com/chromium/deps/libjpeg_turbo/+/9d35298a6223278a66423f828a949d93d94d5911

[fbarchard1, 2016-04-08 23:34:23]

noel, are you able to review?  I see you made some of the recent changes to this
file.

[Noel Gordon, 2016-04-09 00:35:43]

Yes, seems fine. LGTM.

[kjellander_chromium, 2016-04-11 18:20:13]

kjellander@chromium.org changed reviewers:
+ kjellander@chromium.org

[kjellander_chromium, 2016-04-11 18:20:13]

lgtm

[fbarchard1, 2016-04-11 18:46:20]

Description was changed from

==========
Add default variable 'use_system_yasm%': 0

When compiling for NaCL the following build error

native_client/build/gyp_nacl all.gyp -Dgtest_target_type=executable -Dmsan=0
Updating projects from gyp files...
gyp: name 'use_system_yasm' is not defined while evaluating condition
'use_system_yasm==1' in chromium/src/third_party/libjpeg_turbo/libjpeg.gyp

Adding use_system_yasm=0 to the command line works. (use_system_yasm=1 does not
work).
Adding a default to the gyp file allows the build to work without specifying the
default value for this variable.

BUG=None
TESTED=native_client/build/gyp_nacl all.gyp -Dgtest_target_type=executable
-Dmsan=0 -Duse_system_yasm=0
R=noel@chromium.org
==========

to

==========
Add default variable 'use_system_yasm%': 0

When compiling for NaCL the following build error

native_client/build/gyp_nacl all.gyp -Dgtest_target_type=executable -Dmsan=0
Updating projects from gyp files...
gyp: name 'use_system_yasm' is not defined while evaluating condition
'use_system_yasm==1' in chromium/src/third_party/libjpeg_turbo/libjpeg.gyp

Adding use_system_yasm=0 to the command line works. (use_system_yasm=1 does not
work).
Adding a default to the gyp file allows the build to work without specifying the
default value for this variable.

BUG=None
TESTED=native_client/build/gyp_nacl all.gyp -Dgtest_target_type=executable
-Dmsan=0 -Duse_system_yasm=0
R=kjellander@chromium.org, noel@chromium.org

Committed:
https://chromium.googlesource.com/chromium/deps/libjpeg_turbo/+/9d35298a62232...
==========

[fbarchard1, 2016-04-11 18:46:21]

Committed patchset #2 (id:20001) manually as
9d35298a6223278a66423f828a949d93d94d5911 (presubmit successful).