geanylua: Do not accept Lua5.2 as the plugin doesn't build with it

[b4n]

Make sure the found Lua package is version 5.1 and not newer, as 5.2
breaks compilation.

The issue with 5.2 was reported by an user on IRC.

[frlan]

Can you add also something to wscript?

[b4n]

@frlan food remark, fixed. It works but it might be quite ugly as I don't know much about Waf (e.g. I didn't find a better way to check for < 5.2, but admittedly I couldn't find the canonical docs for conf.check_cfg()).

[eht16]

pkg-config also knows --max-version but for lua-5.1 we probably would need to set --max-version 5.1.99 or something. So I actually think your current version constraint isn't that ugly.

[b4n]

@eht16 yeah I found out about max_version but as you say it's a <= check, so not what we need here.
And ok, if you can't tell me there's a better way to do it there mustn't be any I guess :)

[eht16]

Yes, I don't know a better solution. Though I don't agree that this is the same as there is no better solution :).

Let's merge it.