From 092299036705eb597f6c9c3c1cb9939d5fb9d131 Mon Sep 17 00:00:00 2001
From: Matthew Lugg <mlugg@mlugg.co.uk>
Date: Mon, 17 Nov 2025 01:51:11 +0100
Subject: [PATCH] std.Build.Step: send messages to compiler as little-endian

Little-endian is what `std.zig.Server` expects, but the old logic just
send the raw bytes of the struct, so sent in native endian (causing a
crash on big-endian targets).
---
 lib/std/Build/Step.zig | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/lib/std/Build/Step.zig b/lib/std/Build/Step.zig
index f4387a2480..8ee686e44e 100644
--- a/lib/std/Build/Step.zig
+++ b/lib/std/Build/Step.zig
@@ -680,7 +680,10 @@ fn sendMessage(file: std.fs.File, tag: std.zig.Client.Message.Tag) !void {
         .tag = tag,
         .bytes_len = 0,
     };
-    try file.writeAll(std.mem.asBytes(&header));
+    var w = file.writer(&.{});
+    w.interface.writeStruct(header, .little) catch |err| switch (err) {
+        error.WriteFailed => return w.err.?,
+    };
 }
 
 pub fn handleVerbose(