CMake: avoid warnings with CMake 3.10+ and CMAKE_AUTOMOC set.

Co-authored-by: Andy Maloney <asmaloney@gmail.com>

CMakeLists.txt

@@ -30,6 +30,12 @@ if(HUNTER_ENABLED)
     include(${CMAKE_CURRENT_LIST_DIR}/package/hunter/HunterInit.cmake)
 endif()
 
+# If CMAKE_AUTOMOC is set, all uses of corrade_add_resource() would otherwise
+# complain on 3.10 that AUTOMOC is not processing GENERATED files
+if(POLICY CMP0071)
+    cmake_policy(SET CMP0071 NEW)
+endif()
+
 project(Magnum CXX)
 
 if(HUNTER_ENABLED)

doc/changelog.dox

@@ -359,6 +359,8 @@ See also:
     same effect. See @ref building-cross-android, @ref platforms-android and
     [mosra/magnum#310](https://github.com/mosra/magnum/issues/310) for more
     information.
+-   Suppressing a CMake policy-related warning if the global `CMAKE_AUTOMOC` is
+    set on CMake 3.10+ (see [mosra/magnum#504](https://github.com/mosra/magnum/pull/504))
 
 @subsection changelog-latest-bugfixes Bug fixes