cmake warning : `DOWNLOAD_EXTRACT_TIMESTAMP option was not given`

[zhongfly]

Cmake 3.24 change log:
The ExternalProject module ExternalProject_Add() command gained a new DOWNLOAD_EXTRACT_TIMESTAMP option for controlling whether the timestamps of extracted contents are set to match those in the archive when the URL download method is used. Policy CMP0135 was added to enable the option by default.

CMake Warning (dev) at /usr/share/cmake/Modules/ExternalProject.cmake:3071 (message):
  The DOWNLOAD_EXTRACT_TIMESTAMP option was not given and policy CMP0[135](https://github.com/zhongfly/mpv-winbuild/runs/7898409450?check_suite_focus=true#step:11:136) is
  not set.  The policy's OLD behavior will be used.  When using a URL
  download, the timestamps of extracted files should preferably be that of
  the time of extraction, otherwise code that depends on the extracted
  contents might not be rebuilt if the URL changes.  The OLD behavior
  preserves the timestamps from the archive instead, but this is usually not
  what you want.  Update your project to the NEW behavior or specify the
  DOWNLOAD_EXTRACT_TIMESTAMP option with a value of true to avoid this
  robustness issue.
Call Stack (most recent call first):
  /usr/share/cmake/Modules/ExternalProject.cmake:4167 (_ep_add_download_command)
  toolchain/binutils.cmake:1 (ExternalProject_Add)
  toolchain/CMakeLists.txt:16 (include)
This warning is for project developers.  Use -Wno-dev to suppress it.

[adlerzei]

I think because of this fix the build fails on Cygwin (3.3.6, current version), do you know how I can handle this?

$ cmake -DTARGET_ARCH=x86_64-w64-mingw32 -G Ninja ..
CMake Error at CMakeLists.txt:9 (cmake_policy):
  Policy "CMP0135" is not known to this version of CMake.


-- Parsing 8 toolchain packages
CMake Error at /usr/share/cmake-3.23.2/Modules/ExternalProject.cmake:2509 (message):
  error: could not find svn for checkout of amf-headers
Call Stack (most recent call first):
  /usr/share/cmake-3.23.2/Modules/ExternalProject.cmake:3640 (_ep_add_download_command)
  packages/amf-headers.cmake:1 (ExternalProject_Add)
  packages/CMakeLists.txt:98 (include)

[zhongfly]

could not find svn for checkout of amf-headers
Maybe you should install svn(subversion) ?

[adlerzei]

Thanks for the fast reply but my comment referred to the upper error message "Policy "CMP0135" is not known to this version of CMake." Sorry that I did not make this clear.

Can anyone help with this error?