Check CMake TLS functioning
CMake itself is built with SSL by default.
If a user mistakenly builds CMake without SSL support, this is generally not usable as the vast majority of Internet sites require SSL / TLS to function.
Confusing errors result for CMake network operations like file(DOWNLOAD)
in this case.
CMake has a simple capabilities check:
cmake_minimum_required(VERSION 3.25)
execute_process(COMMAND ${CMAKE_COMMAND} -E capabilities OUTPUT_VARIABLE cap)
string(JSON has_tls GET ${cap} "tls")
message(STATUS "${CMAKE_COMMAND} TLS available: ${has_tls}")
To progamatically confirm that TLS and certificates are working, consider check_tls.
For a more complete check consider check_https.cmake