fix Issue 22727 ImportC: add __stdcall Windows calling convention

[WalterBright]

Works same as extern (Windows) in D.

This is a partial fix for https://issues.dlang.org/show_bug.cgi?id=22727 in that it does not implement __fastcall. There are no plans to implement __fastcall.

__stdcall is poorly documented by Microsoft. Figuring out where it can appear in the grammar is the result of trial and error.

[dlang-bot]

Thanks for your pull request, @WalterBright!

Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	22727	major	ImportC: support for __stdcall and __fastcall is necessary for 32-bit Windows builds

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#13614"

[WalterBright]

buildkite dmd/druntime fails with:

Error: The command exited with status 2

of which no illumination is given in the voluminous log file. It's likely a heisenbug, as this change has nothing to do with druntime.

The log file is also full of exceptions and other faults, that seem to be ignored.

[thewilsonator]

There was one about __xopsuchandsuch that I'm pretty sure could be related to that.

[ibuclaw]

If in doubt, rebase local branch on current head. Likely just mismatching runtime and compiler (which wouldn't happen if they were in the same repo).

[WalterBright]

@ibuclaw thanks, trying that.

Why is buildkite retesting druntime anyway? Aren't all the endless other builds doing that enough?

[ibuclaw]

@ibuclaw thanks, trying that.

Why is buildkite retesting druntime anyway? Aren't all the endless other builds doing that enough?

Would it be building it via dub? Just hazarding a guess though.