Add RetroAchievements support

[nfp0]

All bsnes and higan cores in Retroarch, besides this one, support RetroAchievements (even higan Accuracy and nSide Balanced, contrary to the info in the docs).

It would be great to have this excellent up-to-date core also supporting RetroAchievements. Maybe code from the other bsnes/higan cores can be ported to this one to save time.

[nfp0]

According to a contributor on the upstream repository, the missing implementation is this:

bsnes/bsnes/target-libretro/libretro.cpp

Lines 711 to 721 in 3cc8c58

	// Currently, there is no safe/sensible way to use the memory interface without severe hackery.
	// Rely on higan to load and save SRAM until there is really compelling reason not to.
	RETRO_API void *retro_get_memory_data(unsigned id)
	{
	return nullptr;
	}
	RETRO_API size_t retro_get_memory_size(unsigned id)
	{
	return 0;
	}

Byuu says he won't do it himself but he'll be happy to accept a pull request if anyone implements this.
Is this a tall order, considering all previous higan/bsnes cores already implemented this?

[1985a]

I don't know why, but this was working to my few versions back,now it doesn't

[nfp0]

@1985a Are you sure you weren't using one of the older bsnes/higan/nSide cores?
This core didn't exist a while back.

[1985a]

I was using it the actual version of bsnes. Then one day it just gone, RA didn't work.

[nfp0]

Are you talking about the bsnes 094 version? That's still available. It was renamed to bsnes 2014, and yes, that old version supports RetroAchievements.

[1985a]

no, I'm not using that version. Few versions below, I remember using bsnes, almost when it came the first time, when byuu, said I'm working with some guys from Retroarch to bring bsnes as a core.

They are some logs on Github. Look for Jamiras, he is the guy who has been working on RA.

[nfp0]

I've searched and I haven't found anything from Jamiras in this or the upstream repo.
Approximately how long ago was that? Months? Years?