fix: js2c compilation failure

https://chromium-review.googlesource.com/c/chromium/src/+/6950738

See patch description explaining MacOS 26 SDK headers incompatibility.

patches/node/.patches

@@ -52,3 +52,4 @@ chore_exclude_electron_node_folder_from_exit-time-destructors.patch
 api_remove_deprecated_getisolate.patch
 src_switch_from_get_setprototype_to_get_setprototypev2.patch
 fix_replace_deprecated_setprototype.patch
+fix_js2c_including_mac_sdk_headers_twice.patch

patches/node/fix_js2c_including_mac_sdk_headers_twice.patch

@@ -0,0 +1,28 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Samuel Maddock <smaddock@slack-corp.com>
+Date: Wed, 8 Oct 2025 10:50:03 -0400
+Subject: fix: js2c including mac sdk headers twice
+
+https://chromium-review.googlesource.com/c/chromium/src/+/6950738
+
+Chromium has set the minimum MacOS SDK version to 26. With this
+change, it seems to introduce an incompatibility when compiling
+using clang modules. Disabling them seems to resolve the issue.
+
+diff --git a/unofficial.gni b/unofficial.gni
+index a64d2e4ac475abc049fff7ea62ec76de565a747d..61aeac679a90832a1d9f559a4eb880362bce038d 100644
+--- a/unofficial.gni
++++ b/unofficial.gni
+@@ -350,6 +350,12 @@ template("node_gn_build") {
+     include_dirs = [ "src", "tools" ]
+     configs += [ "//build/config/compiler:no_exit_time_destructors" ]
+ 
++    # Fix for MacOSX26 SDK headers included twice due to usage of clang modules.
++    # Included once as a C header and again as C++.
++    if (is_mac) {
++      use_libcxx_modules = false
++    }
++
+     if (!is_win) {
+       defines += [ "NODE_JS2C_USE_STRING_LITERALS" ]
+     }