FetchContent_Declare uses DOWNLOAD_EXTRACT_TIMESTAMP which is incompatible with CMake < 3.24

[klmckeig]

@mihaic @rfsaliev SVS c binding make file has DOWNLOAD_EXTRACT_TIMESTAMP argument in FetchContent_Declare. This was only available in CMake 3.24 and newer. Amazon Linux ships with CMake 3.22.2. So it will trigger an error

CMake Error at /usr/share/cmake/Modules/ExternalProject.cmake:2806 (message):
  At least one entry of URL is a path (invalid in a list)
Call Stack (most recent call first):
  /usr/share/cmake/Modules/FetchContent.cmake:1075 (message):
    CMake step for svs failed: 1

Environment
CMake version: 3.22.2
Compiler: GCC 11.5.0
OS: Amazon Linux 2023 (Linux x86_64)
Build command: cmake -S bindings/c -B build -DSVS_RUNTIME_ENABLE_LVQ_LEANVEC=ON

Suggested Fix

if(CMAKE_VERSION VERSION_GREATER_EQUAL "3.24")
    set(_svs_fetch_timestamp DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
else()
    set(_svs_fetch_timestamp "")
endif()
FetchContent_Declare(
    svs
    URL ${SVS_URL}
    ${_svs_fetch_timestamp}
)

[klmckeig]

fix-cmake-fetch-timestamp.patch

[mihaic]

Is it actually necessary to use DOWNLOAD_EXTRACT_TIMESTAMP TRUE, @rfsaliev? If I understand correctly, because the minimum version we specify is 3.21, CMake >=3.24 behaves as if DOWNLOAD_EXTRACT_TIMESTAMP TRUE is given even if it is not given. If we want to suppress the policy change warning, we should set the corresponding policy CMP0135.