OpenGL is deprecated on MacOS, add Metal implementation

[erkkah]

To make TIGR live alive on MacOS, a Metal implementation should be added and me made the default. The OpenGL version can be kept as a fallback.

[erkkah]

Or maybe just make a plain coregraphics version..

[r-lyeh]

Is it worth the effort? I removed DirectX from Win32 port just because it was not portable enough for other platforms. I'd rather stick to common rendering APIs.

Btw found this somewhere else:

#ifdef __APPLE__
#define GL_SILENCE_DEPRECATION
#include <OpenGL/gl.h>
#else
#include <GL/gl.h>
#endif

[erkkah]

It's not worth it now. We'll see what happens. I'll try the GL_SILENCE_DEPRECATION define for now.

[BenStigsen]

Any thoughts on a Metal backend for TIGR now?

[erkkah]

Hi @BenStigsen. I don't have the time, but PRs are always welcome.

[BenStigsen]

That is understandable. It's not critical in my case, but I will look into it in the future, but I cannot guarantee that anything will come of it.