Merge pull request #1414 from admshao/remove-cmp0072-warning

cmake: Prevent policy CMP0072 warning

CMakeLists.txt

@@ -1,5 +1,10 @@
 cmake_minimum_required(VERSION 2.8.12)
 
+if (UNIX AND POLICY CMP0072)
+	# In case of both legacy and glvnd OpenGL libraries found. Prefer GLVND
+	cmake_policy(SET CMP0072 NEW)
+endif()
+
 project(obs-studio)
 
 option(BUILD_CAPTIONS "Build captions" FALSE)