Update CMakeLists.txt to work with CMake 4

[NHOrus]

CMake 4 dropped compatibility with CMake < 3.5

See https://bugs.gentoo.org/951932

[Blzut3]

While there's probably no reason not to bump the minimum to 3.5 anyway, this should really be switching to the version range syntax. Kitware isn't forcing the minimum to be raised, they're just requiring that the compatibility policies be accepted. So if the project doesn't require backwards compat then it should be:

cmake_minimum_required(VERSION 3.5...4.0)
if(CMAKE_VERSION VERSION_LESS 3.12)
	cmake_policy(VERSION ${CMAKE_VERSION})
endif()

[coelckers]

How old is 3.5? What's this need to handle support for such ancient versions? Does it even still work? Are there relevant platforms that don't have anything more recent?

We should set a reasonable minimum that we know is supported everywhere, not something ancient that the current file still suports by happenstance!

[madame-rachelle]

If you really want to know, ACC for DOS is still compiled the old fashioned way. Using Makefile.

[coelckers]

Yes, but that is needed for the few holdouts that still use Wadauthor, because it screwed up so badly that it doesn't work with a Windows version of it.

Although, thruth be told, that probably won't work on a 64 bit system anymore...

I'll never understand this compulsive need for ultimate backwards compatibility in open source development.

[NHOrus]

https://repology.org/project/cmake/versions
According to this, 3.11 in old Alpine. Let's not indulge poor unfortunate souls who use CentOS 7.
I'll say 3.20+ in something modern, 3.11+ in something less modern but still sane.

[madame-rachelle]

Changed to the range syntax as suggested. To be honest if anyone is using CentOS they're getting what they asked for, I'm not going to lose sleep over that.

[Blzut3]

The modern target based approach of writing CMake has been supported since 3.0 (really 2.8.11 give or take but not worth thinking about). There hasn't been a dramatic shift in how things are written since then. So for trivial CMake projects like this one I think setting the minimum to 3.5 sends a clear enough message that we don't care about legacy CMake patterns.

For non-trivial projects I would say the point where you hit by all practical measures 100% of users today is 3.18. RHEL actually isn't a problem anymore in that regard. They actually release updated toolchains throughout the support period these days. So I believe RHEL 8 has something like CMake 3.26 and GCC 14 available. (RHEL 7 did some something similar, but it wasn't as fully baked. That's end of life now anyway.)