From 124448c1b6d73df6f20901888c79435e4d9e3da7 Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Thu, 20 Jul 2023 16:00:11 +0200
Subject: [PATCH] Include system headers path when targeting assembly_with_cpp

This is consistent with what clang and gcc are doing, because
headers such as <cet.h> are specifically designed to be used
in the context of assembly code.

Fixes #16449
---
 src/Compilation.zig | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Compilation.zig b/src/Compilation.zig
index 3a95f4831a..7d66c78a63 100644
--- a/src/Compilation.zig
+++ b/src/Compilation.zig
@@ -4438,6 +4438,12 @@ pub fn addCCArgs(
         },
         .shared_library, .ll, .bc, .unknown, .static_library, .object, .def, .zig, .res => {},
         .assembly, .assembly_with_cpp => {
+            if (ext == .assembly_with_cpp) {
+                const c_headers_dir = try std.fs.path.join(arena, &[_][]const u8{ comp.zig_lib_directory.path.?, "include" });
+                try argv.append("-isystem");
+                try argv.append(c_headers_dir);
+            }
+
             // The Clang assembler does not accept the list of CPU features like the
             // compiler frontend does. Therefore we must hard-code the -m flags for
             // all CPU features here.