[clang] [clang] Don't use -Wno-nested-anon-types on GCC (PR #95029)

[Martin Storsjö via cfe-commits]

https://github.com/mstorsjo created https://github.com/llvm/llvm-project/pull/95029

GCC usually doesn't warn about unrecognized -Wno-<foo> options, if no diagnostics are printed. However if some diagnostics are printed, it also mentions that there were unrecognized -Wno-<foo> options.

Before 4feae05c6abda364a9295aecfa600d7d4e7dfeb6, we checked for whether -Wnested-anon-types was supported, and added the -Wno-<foo> form if the positive form of the option was supported.

As of GCC 14, -Wnested-anon-types isn't supported, thus limit the use of the option to actual Clang (and still only while using the GCC compatible driver).

This avoids unnecessary mentions about unrecognized -Wno-<foo> options when building with GCC.

>From 4af34cd1a03064a3f5966f8f33bccdec940def89 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Martin=20Storsj=C3=B6?= <martin at martin.st>
Date: Mon, 10 Jun 2024 22:30:59 +0300
Subject: [PATCH] [clang] Don't use -Wno-nested-anon-types on GCC

GCC usually doesn't warn about unrecognized -Wno-<foo> options,
if no diagnostics are printed. However if some diagnostics are
printed, it also mentions that there were unrecognized -Wno-<foo>
options.

Before 4feae05c6abda364a9295aecfa600d7d4e7dfeb6, we checked
for whether -Wnested-anon-types was supported, and added the
-Wno-<foo> form if the positive form of the option was supported.

As of GCC 14, -Wnested-anon-types isn't supported, thus limit
the use of the option to actual Clang (and still only while using
the GCC compatible driver).
---
 clang/CMakeLists.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/clang/CMakeLists.txt b/clang/CMakeLists.txt
index 2ac0bccb42f50..2b5269f2ce2e7 100644
--- a/clang/CMakeLists.txt
+++ b/clang/CMakeLists.txt
@@ -350,7 +350,9 @@ if (LLVM_COMPILER_IS_GCC_COMPATIBLE)
     set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -pedantic -Wno-long-long")
   endif ()
 
-  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-nested-anon-types" )
+  if (CMAKE_CXX_COMPILER_ID MATCHES "Clang")
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -Wno-nested-anon-types" )
+  endif ()
 endif ()
 
 # Determine HOST_LINK_VERSION on Darwin.