RFC: New stable compilation base image

[carstene1ns]

With Ubuntu 20.04 LTS support finally coming to an end in 2 months and debian 11 in LTS mode since last year (until June 30th, 2026), we should revise our common minimal required version policy for all projects again.

Our current minimal tested versions include:

• CMake 3.16
• G++ 9.3
• SDL 2.0.10 (though we only require 2.0.5, which is untested)

See for reference:

Player/.github/workflows/stable-compilation.yml

Lines 31 to 34 in 857af8e

	# version of: # CMake | g++ | SDL | support end #
	# -------------------------------------------------------------
	- ubuntu:20.04 # 3.16.3 | 9.3.0 | 2.0.10 | LTS (4/25) #
	- debian:11 # 3.18.4 | 10.2.1 | 2.0.14 | oldstable (8/24) #

Furthermore fmt in version 5 and SDL 1.2 (which is dormant anyway).

• There are at least some hacks which can be removed after 0.8.1.

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IMO we can ditch debian 11 after release. There are likely not many users, however some linux handhelds may be affected (e.g. retropie?)
Then we can bump to CMake 3.22 and G++ 11, which has almost full C++20 support.

At least bumping to CMake 3.18 should be safe (though debian backports has even 3.25 available, so interested users can still update if needed).

• Then we need to at least add Ubuntu 24.04 LTS and maybe one more to our workflow.

Question is if this affects some of our more exotic platforms and libretro builds, since there could be some limited support.

[Ghabry]

Imo Debian 11 should stay to have at least some coverage for older compilers. The C++20 support of g++10 looks already pretty solid. At least all the stuff I would care about such as std::span, std::endian, better comparison (<=>) are already supported.

libretro uses the image libretro-build-amd64-ubuntu:xenial-gcc9 but I think they also have a newer image as some emulators use C++20 or 23 features.

miyoo/dingux: gcc 6.3 lol. NOPE

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Minimal versions:

Bump the SDL2 and CMake requirements (and maybe also other dependencies where backwards support becomes annoying such as ancient fmtlib) to what Debian 11 provides.

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SDL1.2 is still used on crappy handhelds because without GPU acceleration SDL2 is too slow -_- so I will would still keep SDL1.2 on "life support" unless some refactor makes it really non-feasible anymore.

But the Wii support for SDL1.2 can be dropped. I'm currently only building both versions to find bugs in the SDL2 implementation of the Wii.

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C++20 Coroutines could help to replace our Async code with something that has better language support. But honestly I have 0 experience in this field and this looks like a huuuuge rewrite of the codebase.

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Concerning the proprietary compilers for some consoles the oldest appears to be a clang 8 which was the reason for my one small change in the EnumFlags code.

But that's honestly not something I really care about. They can just use an older version of the Player as a base...