I was planning on using PortableGL as a software implementation of
OpenGL, but it's really slow (at least when compared to actual 2D
graphics software renderers). I'll have to actually add a separate
rendering backend for software rendering later instead of trying to
emulate OpenGL in software.
SDL disables OpenGL headers when building for iOS and tvOS, but that
causes our builds to fail. I'm getting conflicting answers on whether or
not OpenGL is supported on iOS and tvOS, but it's the libretro
frontend's job to care about this, not mine. Regardless, I'm gonna need
these OpenGL headers for software rendering on platforms with no OpenGL
support, so I can't tolerate the headers being disabled.
