[4.0] Add GDNative Framework support for macOS, add Unix symlink API.

[bruvzg]

Adds ability to select, load and export (both .dmg and .zip) macOS ".frameworks" as GDNative libraries.
Adds minimal symlink API to DirAccess (frameworks usually contain multiple relative symlinks).

Framework export won't work from Windows (If there are symlinks in the framework). NTFS have support for symlinks, but I do not see any way to get relative symlink target path, all functions seems to return full path. And creating symlinks seems to require privilege elevation. Not sure what to do with it (currently it will print a warning).

Edit: Relative symlinks are supported and DeviceIoControl(FSCTL_GET_REPARSE_POINT) function can get correct relative path, but none of Windows apps seems to use them and all Windows ZIP software extract symlinks as text files with the target path. Even if working readlink equivalent is added, Windows users won't be able to acquire macOS framework with correct structure in the first place.

Version for 3.2 - #46860

[bruvzg]

Actually, just renaming 64 to universal probably won't work and need a bit more changes to the GDNative loading (OS features).

[bruvzg]

Removed separate x86_64 and arm64, it's just an unnecessary complication, default export template is universal and there's no way to determine architecture of the custom export template (implementing MachO header reader is easy, but I do not see any benefits of doing it).

[akien-mga]

Removed separate x86_64 and arm64, it's just an unnecessary complication, default export template is universal and there's no way to determine architecture of the custom export template (implementing MachO header reader is easy, but I do not see any benefits of doing it).

I guess we'll need to clarify the documentation so users know they can put either a universal binary, an x86_64 or an arm64 binary for the single 64 entry (matching their export template).

[akien-mga]

Thanks!