From 6eb55b21daed1ddbf72feae5cb2cc9c9b68ce8a9 Mon Sep 17 00:00:00 2001
From: Xiaofeng Wang <wasphin@gmail.com>
Date: Wed, 28 Aug 2019 08:06:40 +0800
Subject: [PATCH] cmake: check policy first

Fix unkown policy error with higher version cmake, e.g. 3.11.4

Example of error:
> Policy "CMP0074" is not known to this version of CMake.
---
 CHANGELOG.md   | 1 +
 CMakeLists.txt | 5 ++++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 517f52bb..c3ae6873 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -3,6 +3,7 @@ Version 267:
 * Add package for Travis config
 * Fix signed/unsigned mismatch in file_stdio::seek
 * basic_stream dtor cannot throw
+* cmake: check policy first
 
 --------------------------------------------------------------------------------
 
diff --git a/CMakeLists.txt b/CMakeLists.txt
index 7f909763..ac466e89 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -8,7 +8,10 @@
 #
 
 cmake_minimum_required (VERSION 3.5.1)
-cmake_policy (SET CMP0074 NEW)
+
+if (POLICY CMP0074)
+    cmake_policy (SET CMP0074 NEW)
+endif()
 
 #-------------------------------------------------------------------------------