C++-style comments in the test programs

[icculus]

Hit this on a pull request that compiled fine locally:

Can we enable this warning universally in the CMake files, so we catch these failures before pushing?

Or better: can we remove this requirement from the test programs? Since SDL3 itself doesn't have this requirement, it seems silly to have it on the test programs that are only built in the same project file. If someone wants to paste the test code into their own programs, they can trivially fix it to be ANSI C, if they still need that.

(same deal for variables declared in the middle of a scope, honestly.)

[slouken]

We did that intentionally, but yeah, that seems silly now. Fixed!

[Kontrabant]

This was always a pain when hacking up the tests to try and reproduce a bug. Thanks!

[madebr]

We added that to make sure the SDL3 headers are C90 compatible. Applying it to all tests was perhaps a bit too much.

Let's enable C90-mode on a single small test case, e.g. testver.

[slouken]

We added that to make sure the SDL3 headers are C90 compatible. Applying it to all tests was perhaps a bit too much.

Let's enable C90-mode on a single small test case, e.g. testver.

Sounds good, do you want to re-add it for that?

[madebr]

Sounds good, do you want to re-add it for that?

Done in 7b74fbb!

[icculus]

Awesome, thanks everyone!

I'm going to add a low-priority task to the 3.x milestone to go through the test programs and move variable declarations around and convert /* comments */ to // comments where it makes sense, but it's not urgent at all. Just a nice chance for little cleanups at some point.

[icculus]

Oh, also: let's leave the source in the examples directory as C90, since those are explicitly intended to copy/paste into other projects.

(and if this is good enough to check the SDL headers for compatibility on GitHub Actions, that's fine with me and we don't need a special case in the test directory. But that's @madebr's call on what's most appropriate here.)