`windows-rdl` / clang: unknown type name HRESULT

[riverar]

C header (simplified):

HRESULT STDMETHODCALLTYPE NoRegCoCreate();

Currently panics:

thread 'main' (85492) panicked at build.rs:13:10:
  called `Result::unwrap()` on an `Err` value:
  error: unknown type name 'HRESULT'
   --> .windows/header.h:14:1
  stack backtrace:
     0: std::panicking::panic_handler
               at /rustc/14196dbfa3eb7c30195251eac092b1b86c8a2d84/library\std\src\panicking.rs:689
     1: core::panicking::panic_fmt
               at /rustc/14196dbfa3eb7c30195251eac092b1b86c8a2d84/library\core\src\panicking.rs:80
     2: core::result::unwrap_failed
               at /rustc/14196dbfa3eb7c30195251eac092b1b86c8a2d84/library\core\src\result.rs:1867
     3: build_script_build::main
     4: <fn() as core::ops::function::FnOnce<()>>::call_once

It was expected to produce RDL:

#[win32]
mod Test {
    #[library("test.dll")]
    extern fn NoRegCoCreate() -> Windows::Win32::Foundation::HRESULT;
}

[kennykerr]

In this case, the error is valid:

  error: unknown type name 'HRESULT'
   --> .windows/header.h:14:1

The HRESULT is not defined. Include a definition and it should work. A separate issue is adding support for reference metadata that will map these types to preexisting metadata. That's mostly plumbed in but not quite finished.

[kennykerr]

#4219 should deal with this.