Add TIC-80 libretro renderer

[RobLoach]

This adds a TIC-80 libretro core for playing TIC-80 cartridges in RetroArch. There are some issues that I'd love attention on...

TODO

• Crackling audio
• Fix up the color palette
• Move libretro-common to 3rd-party submodule?
• Is set(CMAKE_POSITION_INDEPENDENT_CODE ON) in the correct place?
• Clean up more of the code
• Platform Testing
  • Linux
  • MacOSX
  • Windows
  • Raspberry Pi
• Update the Makefile with libretro buildbot PLATFORM definitions (cross-compile)

Usage

1. Make sure RetroArch is installed.
2. Build it

   cmake .
   make
   

3. Run it

   retroarch -L lib/tic80_libretro.so demos/sfx.tic
   

Screenshot

Here is 8-Bit Panda running through the libretro core...

Fixes #519 libretro/libretro-lutro#52

[nesbox]

I think it would be better if you move tic80_libretro.c and dependent files to the src/system folder.
@RobLoach What do you think?

[RobLoach]

How about src/system/libretro/tic80_libretro.c? Don't want to clutter the folder too much.

[RobLoach]

Moved to src/system/libretro. Thanks!

[RobLoach]

Lots of commits. When merging, you may want to do a squash & merge. Or not, I'll leave that to you 😄

[nesbox]

let's merge it :)

[paradadf]

When the makefile is properly updated, I plan to add this to recalbox. Thanks both for your work!

[hugh-hoang]

@RobLoach Sorry if this is a dumb question because I have very limited knowledge on how cross compiling work (still learning...) but is this possible to make more build targets for this core for the Nintendo devices such as 3DS and Switch? Retroarch running there with the devkitpro toolchains.

Thanks!

[RobLoach]

@hugh-hoang Quite possibly, yes! While I haven't tested it, nor do I understand it entirely, but it should be possible to...

1. git clone https://github.com/libretro/libretro-super.git
2. Add the platform recipe to https://github.com/libretro/libretro-super/tree/master/recipes
3. Run...

   ./libretro-fetch.sh tic80
   SINGLE_CORE=tic80 ./libretro-buildbot-recipe.sh recipes/nintendo/libnx
   

[hugh-hoang]

@RobLoach Cool thanks, thats a good start and I will try then we will see.

[BarOSGithub]

Please make a .dol version for the Wii.