From 61809b6e221bc300638ce919e3a7c540d7eb4b5b Mon Sep 17 00:00:00 2001
From: Gaute Lindkvist <lindkvis@gmail.com>
Date: Wed, 23 Sep 2020 14:35:19 +0200
Subject: [PATCH] Require C++17

---
 CMakeLists.txt | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d343f14e7c..397b57d8da 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -12,9 +12,15 @@ SET(BUILD_SHARED_LIBS OFF CACHE BOOL "ERT: Build shared libraries")
 
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_SOURCE_DIR}/cmake")
 
-# Use CMake to enforce C++11 when using CMake 3 or newer.
-set(CMAKE_CXX_STANDARD 11)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
+# Use CMake to enforce C++17
+if(CMAKE_VERSION VERSION_LESS 3.8)
+  message(WARNING "CMake version does not support c++17, guessing -std=c++17")
+  set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")
+else()
+  set(CMAKE_CXX_STANDARD 17)
+  set(CMAKE_CXX_STANDARD_REQUIRED ON)
+  set(CMAKE_CXX_EXTENSIONS OFF)
+endif()
 
 ################################################################################
 # Setup the main platform defines