vendor-hermes: advance pin to include upstream napi C-linkage fix

Move the pinned Hermes commit forward from 0ae42446 to efcf68e2 on the
static_h branch (a descendant, 18 commits ahead). The only relevant change
in that range is facebook/hermes#2106 "give hermes_napi.h public API C
linkage", which wraps the public hermes_napi_* entry points in extern "C".

That is exactly the fix we were applying locally after cloning: without C
linkage the mangled hermes_napi_create_env symbol stayed out of the
framework export table under Hermes' global -fvisibility=hidden. Now that
the fix is upstream at the pinned commit, drop patchHermesNapiVisibility and
its header-anchor constants entirely — the vendored checkout exports the
entry points as-is.

No commit in the bumped range touches getVMRuntimeUnsafe or the IHermes JSI
interface we depend on, so the unstable-accessor rationale for pinning still
holds.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TVfanKvtyfSsoMgZv3DJtY

Author: claude

packages/host/src/node/cli/hermes.ts

@@ -21,45 +21,22 @@ const HERMES_GIT_URL = "https://github.com/facebook/hermes.git";
 // Node-API implementation under `API/napi`. Bump deliberately: the JSI
 // accessor we rely on (`getVMRuntimeUnsafe`) is documented as unstable, so we
 // vendor a known-good commit rather than tracking a moving branch.
-const HERMES_GIT_SHA = "0ae42446d1ae669508368b0a18e60c789f76735d";
+//
+// This commit includes facebook/hermes#2106 ("give hermes_napi.h public API C
+// linkage"), which wraps the public `hermes_napi_*` entry points (e.g.
+// `hermes_napi_create_env`) in `extern "C"`. Without it those declarations got
+// C++ linkage: the mangled symbols stayed out of the framework's export table
+// under Hermes' global `-fvisibility=hidden`, and consumers linking the
+// framework hit "Undefined symbol: hermes_napi_create_env". We used to patch
+// the header ourselves after cloning; now that the fix is upstream at this pin,
+// no header patching is required.
+const HERMES_GIT_SHA = "efcf68e285865fd9d952070b08e751bcad63f25e";
 
 const platformOption = new Option(
   "--react-native-package <package-name>",
   "The React Native package to vendor Hermes into",
 ).default("react-native");
 
-// The public `hermes_napi_*` entry points (e.g. `hermes_napi_create_env`) are
-// declared in `hermes_napi.h` with `NAPI_EXTERN` (visibility "default") but —
-// unlike the sibling `js_native_api.h` / `node_api.h` headers — without any
-// `extern "C"` wrapping. So they get C++ linkage: the symbols are name-mangled
-// and, because Hermes builds with a global `-fvisibility=hidden`, stay out of
-// the shared framework's export table. We reach `hermes_napi_create_env` from
-// the host module, so consumers linking the framework hit "Undefined symbol".
-//
-// Wrapping the declarations in `EXTERN_C_START` / `EXTERN_C_END` (both already
-// available via the `node_api.h` include) gives them C linkage, so they export
-// under their unmangled C names. This mirrors facebook/hermes#2106.
-const HERMES_NAPI_HEADER = "API/napi/hermes_napi.h";
-const HERMES_NAPI_INCLUDE = '#include "hermes/napi/node_api.h"';
-const HERMES_NAPI_ENDIF = "#endif // HERMES_NAPI_HERMES_NAPI_H";
-
-async function patchHermesNapiVisibility(hermesPath: string) {
-  const headerPath = path.join(hermesPath, HERMES_NAPI_HEADER);
-  const contents = await fs.promises.readFile(headerPath, "utf8");
-  if (contents.includes("EXTERN_C_START")) {
-    return;
-  }
-  assert(
-    contents.includes(HERMES_NAPI_INCLUDE) &&
-      contents.includes(HERMES_NAPI_ENDIF),
-    `Cannot patch ${HERMES_NAPI_HEADER}: expected anchors not found (did the pinned Hermes commit change?)`,
-  );
-  const patched = contents
-    .replace(HERMES_NAPI_INCLUDE, `${HERMES_NAPI_INCLUDE}\n\nEXTERN_C_START`)
-    .replace(HERMES_NAPI_ENDIF, `EXTERN_C_END\n\n${HERMES_NAPI_ENDIF}`);
-  await fs.promises.writeFile(headerPath, patched);
-}
-
 export const command = new Command("vendor-hermes")
   .argument("[from]", "Path to a file inside the app package", process.cwd())
   .option("--silent", "Don't print anything except the final path", false)
@@ -147,9 +124,6 @@ export const command = new Command("vendor-hermes")
           });
         }
       }
-      // Applied unconditionally (idempotent) so an existing checkout from
-      // before this patch also gets fixed.
-      await patchHermesNapiVisibility(hermesPath);
       console.log(hermesPath);
     }),
   );