Disable LLVM's use of strerror_s on Windows

Disable LLVM's use of strerror_s on Windows

If available, LLVM uses Windows' strerror_s function for printing errors.
Because mingw builds link dynamically against msvcrt.dll, clang will not
run on systems (XP) which lack this function in their version of the dll.
Since we still have buildbots which run SCons on XP, we want clang to run
on XP, and strerror_s seems to be the only missing dependence.

NOTRY=true
BUG= https://code.google.com/p/nativeclient/issues/detail?id=3936
R=jfb@chromium.org

Committed: https://chromium.googlesource.com/native_client/src/native_client/+/bd9bca36ad7a42e512245cf298c0f27397073cb8

[Derek Schuff, 2015-03-26 00:07:06]

tested that a binary built this way runs on XP, so will use this workaround.

[JF, 2015-03-26 00:32:44]

You should instead define WINVER to _WIN32_WINNT_WINXP (0x0501).

[JF, 2015-03-26 00:33:55]

On 2015/03/26 00:32:44, JF wrote:
> You should instead define WINVER to _WIN32_WINNT_WINXP (0x0501).

Oh and _WIN32_WINNT to the same thing.

[Derek Schuff, 2015-03-26 16:02:56]

On 2015/03/26 00:33:55, JF wrote:
> On 2015/03/26 00:32:44, JF wrote:
> > You should instead define WINVER to _WIN32_WINNT_WINXP (0x0501).
> 
> Oh and _WIN32_WINNT to the same thing.

stererror_s is not part of the win32 API and is not defined in windows.h though;
will that work?

[Derek Schuff, 2015-03-26 16:37:27]

On 2015/03/26 16:02:56, Derek Schuff wrote:
> On 2015/03/26 00:33:55, JF wrote:
> > On 2015/03/26 00:32:44, JF wrote:
> > > You should instead define WINVER to _WIN32_WINNT_WINXP (0x0501).
> > 
> > Oh and _WIN32_WINNT to the same thing.
> 
> stererror_s is not part of the win32 API and is not defined in windows.h
though;
> will that work?

answer: no, it does not. The autoconf check still finds the declaration, and the
use of the function in the code is conditioned on the autoconf check.

[JF, 2015-03-26 16:47:47]

lgtm, but I do think we want to define WINVER too. Separate change?

[Derek Schuff, 2015-03-26 16:52:42]

Committed patchset #1 (id:1) manually as
bd9bca36ad7a42e512245cf298c0f27397073cb8 (presubmit successful).