From c3eff6ed50f0ffec75133ef02f23cb6d3321dd70 Mon Sep 17 00:00:00 2001
From: Christian Parpart <christian@parpart.family>
Date: Wed, 22 Jul 2020 16:20:59 +0200
Subject: [PATCH] [cmake] C++ version should not be mandated by the toolchain
 setting, as it conflicts with Windows (CI) builds using vcpkg

---
 .circleci/config.yml           | 2 +-
 cmake/EthToolchains.cmake      | 5 +++++
 cmake/toolchains/cxx20.cmake   | 4 ----
 cmake/toolchains/default.cmake | 4 ----
 4 files changed, 6 insertions(+), 9 deletions(-)
 delete mode 100644 cmake/toolchains/cxx20.cmake

diff --git a/.circleci/config.yml b/.circleci/config.yml
index f5ab32ccc..fbe76d594 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -487,7 +487,7 @@ jobs:
     <<: *build_ubuntu2004
     environment:
       CMAKE_BUILD_TYPE: Debug
-      CMAKE_OPTIONS: -DCMAKE_TOOLCHAIN_FILE=cmake/toolchains/cxx20.cmake -DUSE_CVC4=OFF
+      CMAKE_OPTIONS: -DCMAKE_CXX_STANDARD=20 -DUSE_CVC4=OFF
       MAKEFLAGS: -j 10
     steps:
       - checkout
diff --git a/cmake/EthToolchains.cmake b/cmake/EthToolchains.cmake
index a4263b7df..adf0a20a5 100644
--- a/cmake/EthToolchains.cmake
+++ b/cmake/EthToolchains.cmake
@@ -1,3 +1,8 @@
+# Require C++17.
+set(CMAKE_CXX_STANDARD 17) # This requires at least CMake 3.8 to accept this C++17 flag.
+set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
+set(CMAKE_CXX_EXTENSIONS OFF)
+
 if(NOT CMAKE_TOOLCHAIN_FILE)
   # Use default toolchain file if none is provided.
   set(
diff --git a/cmake/toolchains/cxx20.cmake b/cmake/toolchains/cxx20.cmake
deleted file mode 100644
index ad34e5749..000000000
--- a/cmake/toolchains/cxx20.cmake
+++ /dev/null
@@ -1,4 +0,0 @@
-# Require C++20.
-set(CMAKE_CXX_STANDARD 20) # This requires at least CMake 3.12 to understand this C++20 flag
-set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
-set(CMAKE_CXX_EXTENSIONS OFF)
diff --git a/cmake/toolchains/default.cmake b/cmake/toolchains/default.cmake
index 07fc80e8e..e69de29bb 100644
--- a/cmake/toolchains/default.cmake
+++ b/cmake/toolchains/default.cmake
@@ -1,4 +0,0 @@
-# Require C++17.
-set(CMAKE_CXX_STANDARD 17) # This requires at least CMake 3.8 to accept this C++17 flag.
-set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
-set(CMAKE_CXX_EXTENSIONS OFF)