Remove -Werror from pnacl build, due to default switch error in subzero.

Remove -Werror from pnacl build, due to default switch error in subzero.

When compiling using toolchain_build_pnacl.py, we get errors of form:

  Don't use default labels in fully covered switches over enumerations

I tried different combinations of -Wno-covered-switch-default and
-Wno-error=covered-switch-default, but was not able to stop this
error from being generated. Hence, taking the simplier route of
removing -Werror from Makefile.

(see www.llvm.org/docs/CodingStandards.html for more details)

BUG=None
R=stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=6c4fde964a765130547a513ab371002a37c49cba

[Karl, 2014-10-30 18:12:37]

kschimpf@google.com changed reviewers:
+ jvoung@chromium.org, stichnot@chromium.org

[Jim Stichnoth, 2014-10-30 18:20:34]

lgtm

https://codereview.chromium.org/686103006/diff/1/Makefile
File Makefile (right):

https://codereview.chromium.org/686103006/diff/1/Makefile#newcode15
Makefile:15: CXX.Flags += -std=c++11 -Wextra -Wno-error=unused-parameter
Maybe you should remove all the -W flags?  E.g., if our pnacl build scripts are
changed to add -Werror but not -Wextra, some non-Subzero includes might start
producing warnings in the Subzero build that are treated as errors.

And then after the LLVM 3.5 merge, CXX.Flags would be removed entirely.

[Karl, 2014-10-30 19:30:57]

https://codereview.chromium.org/686103006/diff/1/Makefile
File Makefile (right):

https://codereview.chromium.org/686103006/diff/1/Makefile#newcode15
Makefile:15: CXX.Flags += -std=c++11 -Wextra -Wno-error=unused-parameter
On 2014/10/30 18:20:34, stichnot wrote:
> Maybe you should remove all the -W flags?  E.g., if our pnacl build scripts
are
> changed to add -Werror but not -Wextra, some non-Subzero includes might start
> producing warnings in the Subzero build that are treated as errors.
> 
> And then after the LLVM 3.5 merge, CXX.Flags would be removed entirely.

Removed -W flags, and yes, after the merge, remove CXX.flags.

[Karl, 2014-10-30 22:11:20]

Committed patchset #2 (id:20001) manually as
6c4fde964a765130547a513ab371002a37c49cba (presubmit successful).