build: Make it compatible with CMake 4.0

[debarshiray]

Compatibility with versions of CMake older than 3.5 has been removed from CMake 4.0 [1]. This leads to:

  CMake Error at CMakeLists.txt:1 (CMAKE_MINIMUM_REQUIRED):
    Compatibility with CMake < 3.5 has been removed from CMake.

    Update the VERSION argument <min> value.  Or, use the <min>...<max>
    syntax to tell CMake that the project requires at least <min> but
    has been updated to work with policies introduced by <max> or
    earlier.

    Or, add -DCMAKE_POLICY_VERSION_MINIMUM=3.5 to try configuring
    anyway.

It's necessary to be compatible with CMake 4.0 because it is now in Fedora Rawhide. The lack of compatibility with CMake older than 3.5 shouldn't be a big problem because even RHEL 8.10 has CMake 3.26.5.

[1] https://cmake.org/cmake/help/latest/release/4.0.html

[ptoscano]

Hi @debarshiray,

changing the version is only the tip of the iceberg; since that cmake buildsystem is a bit old, I took the opportunity to refresh/improve it a bit: #3522

Because of that, I'm closing this PR -- thanks anyway for it, and for raising the awareness of the cmake compat issue!

[debarshiray]

changing the version is only the tip of the iceberg; since that cmake buildsystem is a bit old, I took the opportunity to refresh/improve it a bit: #3522

Because of that, I'm closing this PR -- thanks anyway for it, and for raising the awareness of the cmake compat issue!

Cool, thanks!