Precompiled Snapshot 159 fails to detect appearance change

[L-TChen]

Describe the bug
The variable v:os_appearance always returns 0 for the compiled binary of Snapshot 159; it works as expected if compiled manually and changing the deployment target to macOS 10.14+ or above.

To Reproduce
Run MacVim in the dark mode and :echo v:os_appearance always shows 0.

Expected behavior
The variable v:os_appearance should be 1 in the dark mode.

Proposed solution
Another binary for macOS 10.14+.

The API used to change the variable is only available on macOS 10.14+ (here). Changing the deployment target to 10.14 is rather radical in my opinion. A temporary solution would be to provide another binary for macOS 10.14+.

[eirnym]

@L-TChen
It's true. However, it peeks correct theme on restart (direct switch doesn't work well) which could be used to fix the problem

[ychin]

It's just a bug in how it did version SDK checks. Will be fixed in next snapshot.

The unfortunate thing is if we have better test suites for these MacVim-specific features it would have been caught in CI. I should probably prioritize that.