From a8b50aae29bc443b44c307c10395ca26186a7e83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?V=C3=ADt=20Ku=C4=8Dera?=
 <26327373+vkucera@users.noreply.github.com>
Date: Thu, 17 Sep 2026 10:54:49 +0200
Subject: [PATCH] Isolate Clang-only CMake flags

---
 dependencies/O2CompileFlags.cmake | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/dependencies/O2CompileFlags.cmake b/dependencies/O2CompileFlags.cmake
index 00e05d503cb99..2871f0be930c7 100644
--- a/dependencies/O2CompileFlags.cmake
+++ b/dependencies/O2CompileFlags.cmake
@@ -108,8 +108,12 @@ if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
                 WARNINGS ${O2_NEW_COMPILER_WARNINGS_NO_ERROR})
 endif()
 
-string(JOIN " " CMAKE_C_WARNINGS "-Wno-unknown-warning-option" "-Wno-vla-cxx-extension" ${O2_C_ENABLED_WARNINGS} ${O2_C_ENABLED_WARNINGS_NO_ERROR} ${O2_NEW_COMPILER_NO_ERROR_FLAGS})
-string(JOIN " " CMAKE_CXX_WARNINGS "-Wno-unknown-warning-option" "-Wno-vla-cxx-extension" ${O2_CXX_ENABLED_WARNINGS} ${O2_CXX_ENABLED_WARNINGS_NO_ERROR} ${O2_NEW_COMPILER_NO_ERROR_FLAGS})
+string(JOIN " " CMAKE_C_WARNINGS ${O2_C_ENABLED_WARNINGS} ${O2_C_ENABLED_WARNINGS_NO_ERROR} ${O2_NEW_COMPILER_NO_ERROR_FLAGS})
+string(JOIN " " CMAKE_CXX_WARNINGS ${O2_CXX_ENABLED_WARNINGS} ${O2_CXX_ENABLED_WARNINGS_NO_ERROR} ${O2_NEW_COMPILER_NO_ERROR_FLAGS})
+if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+  string(APPEND CMAKE_C_WARNINGS " -Wno-unknown-warning-option -Wno-vla-cxx-extension")
+  string(APPEND CMAKE_CXX_WARNINGS " -Wno-unknown-warning-option -Wno-vla-cxx-extension")
+endif()
 
 string(REGEX MATCH "-O[0-9]+" CMAKE_FLAGS_OPT_VALUE "${CMAKE_CXX_FLAGS}")
 if(NOT CMAKE_FLAGS_OPT_VALUE OR CMAKE_FLAGS_OPT_VALUE STREQUAL "-O0" OR CMAKE_FLAGS_OPT_VALUE STREQUAL "-O1")