From 11f7fb19283e14db86100fff14a8eb9cd525b6a2 Mon Sep 17 00:00:00 2001
From: "Alexander A. Klimov" <alexander.klimov@icinga.com>
Date: Mon, 15 Aug 2022 17:29:23 +0200
Subject: [PATCH] CMakeLists.txt: don't surprise (i.e. terminate) CMake < 3.8
 (on SLES 12.5)

with "set(CMAKE_CXX_STANDARD 17)" which it doesn't know.
---
 CMakeLists.txt | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 51c6c93ff..53a11b10b 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -2,9 +2,16 @@
 
 cmake_minimum_required(VERSION 2.8.8)
 set(BOOST_MIN_VERSION "1.66.0")
-set(CMAKE_CXX_STANDARD 17)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-set(CMAKE_CXX_EXTENSIONS OFF)
+
+if("${CMAKE_VERSION}" VERSION_LESS "3.8") # SLES 12.5
+  if(NOT MSVC)
+    set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17")
+  endif()
+else()
+  set(CMAKE_CXX_STANDARD 17)
+  set(CMAKE_CXX_STANDARD_REQUIRED ON)
+  set(CMAKE_CXX_EXTENSIONS OFF)
+endif()
 
 project(icinga2)
 list(APPEND CMAKE_MODULE_PATH "${CMAKE_CURRENT_SOURCE_DIR}/cmake")