fix: for issue #569, now use the guard to turn it off (#617)

CMakeLists.txt

@@ -255,7 +255,11 @@ if(ENABLE_CJSON_TEST)
 endif()
 
 #Create the uninstall target
-add_custom_target(uninstall "${CMAKE_COMMAND}" -P "${PROJECT_SOURCE_DIR}/library_config/uninstall.cmake")
+option(ENABLE_CJSON_UNINSTALL "Enable creating uninstall target" ON)
+if(ENABLE_CJSON_UNINSTALL)
+  add_custom_target(uninstall "${CMAKE_COMMAND}" -P
+    "${PROJECT_SOURCE_DIR}/library_config/uninstall.cmake")
+endif()
 
 # Enable the use of locales
 option(ENABLE_LOCALES "Enable the use of locales" ON)