RFR: 8293088: Fix compilation with the new Visual Studio preprocessor

[Daniel Jeliński]

On Tue, 30 Aug 2022 12:08:09 GMT, Daniel Jeliński <djelinski at openjdk.org> wrote:

> Fix compilation with Zc:preprocessor enabled. 
> 
> The flag itself will be enabled in [JDK-8247283](https://bugs.openjdk.org/browse/JDK-8247283); I enabled the flag using instructions found in Magnus's comment on that issue.
> 
> Windows 10 SDK version 2104 (10.0.20348.0) is required for successful compilation. Compilation fails with a warning (treated as error by default) with older versions of Windows 10 SDK.
> 
> I verified that the compilation completes successfully with this patch, both in debug and in release mode, both with and without Zc:preprocessor.

I verified that client tests still pass. I also verified on a separate project that merging strings with and without ## is equivalent when Zc:preprocessor is absent. When it is present, merging with ## is an error.

I did not verify the output of the changed macros, but I'm pretty confident that their behavior will not change. If you could suggest a test, I'll be happy to perform it.

-------------

PR: https://git.openjdk.org/jdk/pull/10080