CMake: Bump maximum policy version to 3.31

With CMake 3.31, there were a few warnings from
CMP0177 "install() DESTINATION paths are normalized".
These occurred because the install(FILES) command in
my_install_man_lang() is called with a DESTINATION path
that contains two consecutive slashes, for example,
"share/man//man1". Such a path is for the English man pages.
With translated man pages, the language code goes between
the slashes. The warning was probably triggered because the
extra slash gets removed by the normalization.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index f47eb36985f5d472a783abad5c4ffc843243d4b3..bc2ff9bbe22e516c1fb18e20b1aa9df013803cdc 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -77,7 +77,7 @@
 #
 #############################################################################
 
-cmake_minimum_required(VERSION 3.20...3.30 FATAL_ERROR)
+cmake_minimum_required(VERSION 3.20...3.31 FATAL_ERROR)
 
 include(CMakePushCheckState)
 include(CheckIncludeFile)