Add support for M1 Macs

[calmsacibis995]

This is a build of Shoebill that has M1 support, with the debugger being left out due to missing symbols.

[calmsacibis995]

Maybe if this gets merged, it will become version 0.0.6. Requires at least Big Sur to run.

[Huntman616]

@calmsacibis995 sorry I haven't been working on this project as much as I should have since I took over from the original developer I could use some more help and collaboration so I sent an invite to you to help update the code so I can run on New Mac's my machine is currently running macOS 13.5 but every little bit of help I can get on this project is appreciated. I also saw your profile. I myself am a collector of vintage computers, and I am interested in emulation of those systems.

[mitchblank]

I can verify that this branch (along with the two 1-liner fixes to fpu.c I mention in #15 and #20) seems to at least start OK on an M1 Macbook Pro running MacOS 15.4

Only immediate issue I have is that at least under the default graphics settings, the display is only in the bottom-left corner of the window:

This is especially annoying because the normal Ctrl+Pinch magnifier shortcut doesn't function when Shoebill is foregrounded... although you can switch to another app, magnify, and then switch to Shoebill

I doubt that graphics issue is M1-related directly though; probably more likely that the OpenGL code isn't scaling something for HiDPI displays that it should. So I think everything in this PR is good.