Unconditional inclusion of possibly non-existing frameworks breaks builds on macOS

[barracuda156]

The following commit have broken builds on earlier macOS where these frameworks do not exist:
b87d80d
00b5362

[doug-walker]

@barracuda156 , the commits you reference seem to rely on frameworks that have been part of macOS for a long time. What version of macOS are you trying to compile on?

[barracuda156]

I was building on 10.6.8. Metal is quite late, apparently, 10.11? ColorSync and CoreGraphics existed for ages, but inside ApplicationServices: direct linking fails, perhaps, up to 10.8 or later.

Worth noting that Metal is almost never actually required, since it is just a proprietary replacement for OpenGL. (vulkan support on macOS relies on Metal via Molten, but that’s the only example I can recall.) Graphic libraries which use Metal often do that conditionally (angle, as a random example).

[doug-walker]

The OS versions we target are primarily driven by the VFX Reference Platform (vfxplatform.org). We try to support at least three years back, so currently the CY2023 platform. The minimum deployment target for CY2023 was macOS 11. So macOS 10.8, let alone 10.6, is not something we are trying to support anymore. (MacOS 10.6 is from 2009.) Trying to adjust our build and include files to conditionally avoid the things you mention would not be a priority for us at this point.