Add Lua 5.1.5 and 5.2.4 source code

[xxyzz]

This pull request adds the Lua 5.1.5 and 5.2.4 source files. The Lua GitHub repo doesn't have tags for those two releases, so I downloaded the code from https://www.lua.org/ftp and added them to the third-party directory.

The test_decrease_memory test failed on Lua 5.1 with error not enough memory, but I'm not sure how to fix it yet.

[scoder]

Thanks. When you write "doesn't have tags", do you mean that it doesn't include the commit IDs either? Meaning, the code is really not there? Or are only the tags missing?

I'd rather not have these sources in the repo. If there's a way to get them via an external subrepo, I'd prefer that. Doesn't have to be github, just some sort-of official repo.

[scoder]

At least for the 5.2 branch, there seem to be commits after 5.2.3:
https://github.com/lua/lua/commits/v5-2

The 5.1 branch has apparently been deleted already.

[xxyzz]

It's kind of complicated because that GitHub repo is "synced from another RCS repository" and the only official site to download their code is https://www.lua.org/ftp. Please see the Lua maintainer's comment at here: lua/lua#16 (comment)

[xxyzz]

The build finally passed this time... Only the test_decrease_memory test failed for Lua 5.1.

[xxyzz]

I guess Lua 5.1 doesn't collect garbage when lua_Alloc failed. Should I just disable test_decrease_memory for Lua 5.1?

[scoder]

At least for the 5.2 branch, there seem to be commits after 5.2.3:
https://github.com/lua/lua/commits/v5-2

I've updated the Lua 5.2 subrepo in the master branch to the latest commit in that branch. Let's use that. The last commit there seems to indicate that Lua 5.2.4 had been released at that point.

Personally, I think that Lua 5.1 is long out of maintenance for good reason, and shouldn't be used any more, but if we can still support it without much effort, then let's just add the sources to Lupa. It just makes the distro and repo a little larger. Someone out there can probably still make use of it.

[xxyzz]

The last commit there seems to indicate that Lua 5.2.4 had been released at that point.

That branch lacks some files in the .tar.gz file but that probably doesn't matter, most C code are the same.

Someone out there can probably still make use of it.

My main reason to create this pull request is for the https://github.com/tatuylonen/wiktextract project, they have to run some Lua 5.1 code because MediaWiki is still using 5.1.5.

[scoder]

Thanks!

[rsiemens]

Personally, I think that Lua 5.1 is long out of maintenance for good reason, and shouldn't be used any more, but if we can still support it without much effort, then let's just add the sources to Lupa. It just makes the distro and repo a little larger. Someone out there can probably still make use of it.

Just another supporting data point for Lua 5.1 inclusion - Redis still bundles Lua 5.1 so being able to easily unit test any lua scripts that will be sent to redis via python is nice.