From 5dd0b43dfc92f0bfa6d039c6337577714561bcb1 Mon Sep 17 00:00:00 2001
From: SquallATF <squallatf@gmail.com>
Date: Sat, 20 Sep 2025 22:29:10 +0800
Subject: [PATCH] Fix clang-cl warning flags: use `/W4` instead of `/Wall`
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This PR fixes the warning flags when building with **clang-cl**.

Previously, the CMake configuration unconditionally added `-Wall -Wextra` for Clang.
However, according to the [clang-cl documentation](https://clang.llvm.org/docs/UsersManual.html#clang-cl), `/Wall` in clang-cl is mapped to `-Weverything`, which enables **all possible warnings**, far more than MSVC’s `/Wall`. This results in a flood of warnings that are not intended.

The original intent was to match MSVC `/W4` (≈ `-Wall -Wextra` in GCC/Clang).
---
 CMakeLists.txt | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 2a02433..9b5b1cb 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -122,7 +122,13 @@ elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "Clang")
   if(CMAKE_CXX_COMPILER_VERSION VERSION_LESS 3.3.0)
     message(FATAL_ERROR "llvm/clang 3.3 or higher required!")
   endif()
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
+  if("${CMAKE_CXX_SIMULATE_ID}" STREQUAL "MSVC" OR "${CMAKE_CXX_COMPILER_FRONTEND_VARIANT}" STREQUAL "MSVC")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} /W4")
+    add_definitions(-DUNICODE -DNOMINMAX)
+    set(CMAKE_DEBUG_POSTFIX _d)
+  else()
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wall -Wextra")
+  endif()
 elseif ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
   if(MSVC_VERSION LESS 1900)
     message(FATAL_ERROR "msvc 2015 or higher required!")