CMake: Missing BYPRODUCT or OUTPUT

CMake Warning (dev):

  Policy CMP0058 is not set: Ninja requires custom command byproducts to be

  explicit.  Run "cmake --help-policy CMP0058" for policy details.  Use the

  cmake_policy command to set the policy and suppress this warning.

  This project specifies custom command DEPENDS on files in the build tree

  that are not specified as the OUTPUT or BYPRODUCTS of any

  add_custom_command or add_custom_target:

   storage/tokudb/PerconaFT/./snappy/lib/libsnappy.a

   storage/tokudb/PerconaFT/./xz/lib/liblzma.a

  For compatibility with versions of CMake that did not have the BYPRODUCTS

  option, CMake is generating phony rules for such files to convince 'ninja'

  to build.

  Project authors should add the missing BYPRODUCTS or OUTPUT options to the

  custom commands that produce these files.