Merge pull request libgit2#4471 from libgit2/cmn/cmake-feature-302

cmake: use a FEATURE_SUMMARY call compatible with 3.0.2

Author: pks-t

CMakeLists.txt

@@ -335,7 +335,8 @@ IF (BUILD_EXAMPLES)
 ENDIF ()
 
 IF(CMAKE_VERSION VERSION_GREATER 3)
-	FEATURE_SUMMARY(WHAT ENABLED_FEATURES DISABLED_FEATURES)
+	FEATURE_SUMMARY(WHAT ENABLED_FEATURES DESCRIPTION "Enabled features:")
+	FEATURE_SUMMARY(WHAT DISABLED_FEATURES DESCRIPTION "Disabled features:")
 ELSE()
 	PRINT_ENABLED_FEATURES()
 	PRINT_DISABLED_FEATURES()