Fix the test setting COMPILE_DEFINITIONS target property

Tests/CompileDefinitions/target_prop/CMakeLists.txt

@@ -3,7 +3,7 @@ project(target_prop)
 
 add_executable(target_prop_executable ../main.cpp)
 
-set_target_properties(target_prop_executable PROPERTIES CMAKE_IS_FUN -DCMAKE_IS_REALLY="Very Fun")
+set_target_properties(target_prop_executable PROPERTIES COMPILE_DEFINITIONS CMAKE_IS_FUN)
 
 set_property(TARGET target_prop_executable APPEND PROPERTY COMPILE_DEFINITIONS CMAKE_IS_REALLY="Very Fun" CMAKE_IS=Fun)
 set_property(TARGET target_prop_executable APPEND PROPERTY COMPILE_DEFINITIONS CMAKE_IS_FUN CMAKE_IS_="Fun")