fix(windows-drivers): parse the iddcx bindgen as C++ (clears struct-tag)

Direct clang test on the box proved IddCx.h parses with 0 errors as C++ but fails
as C (wdk_default has no --language=c++) — the IDARG_* typedef names hit "must use
struct tag" in C mode. Fix generate_iddcx: --language=c++ + keep -DIDD_STUB +
allowlist_recursively(false) + full codegen, so it emits ONLY IddCx items
(structs, the IddFunctions table enums, DDI fn-ptr typedefs) and references
WDF/Win/DXGI types from wdk-sys via `use crate::types::*` (no re-emission, no
blocklist). Reverted the ENABLED_API_SUBSETS Iddcx entry (it wrongly pulled
IddCx into the C-mode constants/types passes).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packaging/windows/drivers/vendor/wdk-sys/build.rs

@@ -145,8 +145,6 @@ const ENABLED_API_SUBSETS: &[ApiSubset] = &[
     ApiSubset::Storage,
     #[cfg(feature = "usb")]
     ApiSubset::Usb,
-    #[cfg(feature = "iddcx")]
-    ApiSubset::Iddcx,
 ];
 
 type GenerateFn = fn(&Path, &Config) -> Result<(), ConfigError>;
@@ -356,18 +354,20 @@ fn generate_iddcx(out_path: &Path, config: &Config) -> Result<(), ConfigError> {
 
     let bindgen_builder = {
         bindgen::Builder::wdk_default(config)?
-            // IddCx headers MUST be in STUB mode (function-table dispatch): IddCxFuncEnum.h otherwise
+            // IddCx.h MUST be parsed as C++: under wdk-sys's default C mode the IDARG_* typedef names
-            // errors "IDDCX_VERSION_MAJOR is not defined", cascading into "must use 'struct' tag" on the
+            // hit clang's "must use 'struct' tag" (verified: IddCx.h parses with 0 errors as C++, fails
-            // IDARG_* types (their version-gated typedefs get skipped). `#define IDD_STUB` is exactly
+            // as C). `IDD_STUB` puts IddCxFuncEnum.h in table-dispatch mode (else its `#error
-            // what the proven wdf-umdf oracle uses. Do NOT add WDF_STUB — wdk-sys parses wdf.h
+            // IDDCX_VERSION_MAJOR is not defined` fires — it's inside `#ifndef IDD_STUB`). Matches the
-            // non-stubbed, and stubbing it only here would desync the WDF types the iddcx module resolves
+            // proven wdf-umdf oracle's `--language=c++` + `#define IDD_STUB`. NOT WDF_STUB (wdk-sys
-            // against, breaking type-identity.
+            // parses wdf.h non-stubbed; stubbing only here would desync WDF type-identity).
+            .clang_arg("--language=c++")
             .clang_arg("-DIDD_STUB")
-            .with_codegen_config((CodegenConfig::TYPES | CodegenConfig::VARS).complement())
+            // Emit ONLY IddCx items (its types + the IddFunctions table enums + the DDI fn-pointer
+            // typedefs) and DON'T recurse into referenced WDF/Win/DXGI types — those resolve to wdk-sys's
+            // shared bindings via `use crate::types::*` in src/iddcx.rs (type-identity, no re-emission,
+            // no fragile blocklist). Full codegen (no .complement()) so the IDARG_* structs are emitted.
+            .allowlist_recursively(false)
             .header_contents("iddcx-input.h", &header_contents)
-            // Allowlist by the "iddcx" path component (separator-agnostic) so ONLY IddCx items are
-            // emitted; the WDF/Win/DXGI types they reference RESOLVE to the shared base/wdf bindings
-            // instead of being redefined.
             .allowlist_file("(?i).*iddcx.*")
     };
     trace!(bindgen_builder = ?bindgen_builder);