ImportC add Windows cl preprocessor #define support

[WalterBright]

Trying it out with Microsoft's preprocessor

[dlang-bot]

Thanks for your pull request, @WalterBright!

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Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub run digger -- build "master + dmd#14151"

[adamdruppe]

How does that testdefine.c actually test the translation? Wouldn't the preprocessor just change that static assert to 3 == 3 without confirming the symbol is seen by D?

[adamdruppe]

cool

[WalterBright]

The following operation failed:
Name: checkwhitespace

It sure would be nice if checkwhitespace bothered to say which file failed. I can't find any files with tabs in them.

[WalterBright]

The code is actually working, the errors are of the form:

 fail_compilation\testTypeof.c(8): Error: `typeof` operator expects an expression or type name in parentheses
 fail_compilation\testTypeof.c(8): Error: identifier or `(` expected
+testTypeof.c

i.e. cl is insisting on randomly inserting the filename into stdout.

[WalterBright]

I'm lost. I don't know where cl is writing the #define's to. It's not emitted to stdout (like sppn.exe does), and it's not in the preprocessed output file (like cpp does). My cl program is too old to support the /PD switch for cl.

Can anyone with a post-2020 cl investigate and let me know? Thanks!

[12345swordy]

What is exactly preventing you from installing the latest VC Walter?

[WalterBright]

I found the problem. Thanks @rainers for your help!

It's working now, except for some strange problem with the auto-tester that seems completely unrelated.

[RazvanN7]

@WalterBright There were some tabs introduced in #14153. But that was fixed by: #14154 . I rebased this PR and everything should be ok now.