From b97eaabb78ac057ca97e82b47cbdd5c450f4ccf3 Mon Sep 17 00:00:00 2001
From: Steven Johnson <srj@google.com>
Date: Fri, 8 Apr 2022 16:24:44 -0700
Subject: [PATCH] Silence "unknown warning" in Clang 13

Clang 13 removed the `return-std-move-in-c++11` warning entirely, so specifying it now warns that the warning is unknown.
---
 src/CMakeLists.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 809b3efdd937..7b2524361a18 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -459,7 +459,6 @@ target_compile_options(
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-missing-prototypes>
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-nonportable-system-include-path>
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-reserved-id-macro>
-        $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-return-std-move-in-c++11>
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-shadow-field-in-constructor>
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-shadow-field>
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-shorten-64-to-32>
@@ -467,6 +466,9 @@ target_compile_options(
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-unused-member-function>
         $<$<CXX_COMPILER_ID:Clang,AppleClang>:-Wno-unused-template>
 
+        # This warning was removed in Clang 13
+        $<$<AND:$<CXX_COMPILER_ID:Clang,AppleClang>,$<VERSION_LESS:$<CXX_COMPILER_VERSION>,13.0>>:-Wno-return-std-move-in-c++11>
+
         $<$<CXX_COMPILER_ID:MSVC>:/W3>
         $<$<CXX_COMPILER_ID:MSVC>:/wd4018>  # 4018: disable "signed/unsigned mismatch"
         $<$<CXX_COMPILER_ID:MSVC>:/wd4141>  # 4141: 'inline' used more than once