From 1b46de5634d4dbb5dacffac6ceecad92e5aabdb7 Mon Sep 17 00:00:00 2001
From: mariuszmaximus <mariusz.maximus@gmail.com>
Date: Sun, 18 Oct 2026 01:11:23 +0200
Subject: [PATCH] Guard WIN32_LEAN_AND_MEAN in the C++20 module

Avoid a macro redefinition warning when WIN32_LEAN_AND_MEAN is
already provided through compiler flags, for example with
-DWIN32_LEAN_AND_MEAN.

This follows the approach previously adopted in #1729.
---
 src/fmt.cc | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/fmt.cc b/src/fmt.cc
index 7f51c356..780e39e9 100644
--- a/src/fmt.cc
+++ b/src/fmt.cc
@@ -101,7 +101,9 @@ module;
 #    include <ext/stdio_filebuf.h>
 #    include <ext/stdio_sync_filebuf.h>
 #  endif
-#  define WIN32_LEAN_AND_MEAN
+#  ifndef WIN32_LEAN_AND_MEAN
+#    define WIN32_LEAN_AND_MEAN
+#  endif
 #  include <windows.h>
 #endif