commit caf0bfa81d1924e84391a1cccbceefa4cc87f880
Author:     Albrecht Schlosser <albrechts.fltk@online.de>
AuthorDate: Fri Sep 18 18:07:18 2020 +0200
Commit:     Albrecht Schlosser <albrechts.fltk@online.de>
CommitDate: Fri Sep 18 18:07:18 2020 +0200

    Avoid CMake developer warning related to OpenGL/CMP0072
    
    Newer CMake versions warn if CMake policy CMP0072 is not set. We're
    using "legacy mode" since we use FindOpenGL with `OPENGL_LIBRARIES`
    and not (yet) the `OpenGL::GL` target.
    
    See https://cmake.org/cmake/help/latest/policy/CMP0072.html

 CMakeLists.txt | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git CMakeLists.txt CMakeLists.txt
index 9693b67..191d0cf 100644
--- CMakeLists.txt
+++ CMakeLists.txt
@@ -28,6 +28,15 @@
 # Minimum CMake version required by FLTK 1.4 (06/2020, work in progress)
 cmake_minimum_required (VERSION 3.2.3 FATAL_ERROR)
 
+# Use "legacy mode" of FindOpenGL (avoid CMake developer warning)
+# Note: we're using FindOpenGL with `OPENGL_LIBRARIES` and not (yet)
+# the `OpenGL::GL` target. May be changed in the future.
+# See https://cmake.org/cmake/help/latest/policy/CMP0072.html
+
+if (POLICY CMP0072)
+  cmake_policy (SET CMP0072 OLD)
+endif ()
+
 #######################################################################
 # define the FLTK project and version
 #######################################################################