[Buildroot] [PATCH V4] sdl2: new package

[Vincent Stehlé]

Hi Guillaume and Romain,

Thank you for your effort on this nice sdl2 buildroot patch. I hope you
are still working on it.

While trying v5 of the path recently, as found in buildroot patchwork, I
needed to add the following line to sdl2.mk:

	SDL2_CONFIG_SCRIPTS = sdl2-config

Without this line, the include path returned by `sdl2-config --cflags`
will be something like /usr/include/SDL2, instead of pointing to the
buildroot staging dir.

You might want to add it to a v6, maybe?

Apart from that, it works fine for me, thanks!

Best regards,

V.