Add libretro support

[beudbeud]

Hi maybe it will be nice to have libretro core from your emulator.

[Korb]

For what?

[beudbeud]

for can use your emulateur in Retroarch.

[r-lyeh]

hello @beudbeud i dont think Spectral will add anything relevant to the retroarch ecosystem since Spectral is not on par compared to more mature emulators like Fuse, SpecEmu, Spectaculator, etc. I'm pretty sure current zx emulation on retroarch is way better than spectral can deliver, at the moment. That being said i'm not totally closed to the idea of having yet another platform supported if the required changes prove to be small and/or contained in few files. I'm leaving the issue open in case some other guy ports the code some day. I guess the shortest path to accomplish that would be to create a new tigr backend with retroarch calls in the backend implementation.

[Korb]

My opinion here doesn't mean much, since I haven't contributed a single line of code to the project.

However, I will note that due to the extreme resource constraints of this project, when choosing between improving it as such and implementing integration with third-party shells, the former seems to be a higher priority for me personally.

At the same time, I can't help but note that RetroArch in its Steam version does not have a single DLC (out of 65 available) that provides it with support for Sinclair ZX Spectrum applications. If I'm right, and the Steam version of RetroArch really doesn't support applications in formats supported by Spectral, making it compatible with RetroArch might be a way to implement some previously published FRs: #7 and #16 — [5], [13], [20], [22], [27], [29], and [41] (+ Steam Cloud).