[clang] [clang][modules] Headers meant to be included multiple times can be completely invisible in clang module builds (PR #83660)

[Ilya Biryukov via cfe-commits]

ilya-biryukov wrote:

> Are your `textual` headers meant to be included more than once? If not, do they use header guards or `#pragma once`?

As I mentioned, the increase is coming from the module files.
The textual headers are header-guarded and not intended to be included more than once.

> clang never transforms #include to #import. It will effectively attempt to transform #include and #import to @import but that's different.

I meant to say that we use module maps to replace `#include` with module imports. Sorry for getting the exact terminology wrong.


https://github.com/llvm/llvm-project/pull/83660