[Bug] "your CLT doesn't support macos11"

# 🐛 Bug

If you're looking to report an issue with the Diem Core project go to https://github.com/libra/libra

## Steps to reproduce

NOTE: this was captured on 1.24.2121

1. try to build diem/reference-wallet on macos 11.2.1
2. as seen in screenshot, build fails with "your CLT doesn't support macos11"

perhaps docs need to be updated with a workaround

** Error message or problem **
```
"your CLT doesn't support macos11"

```

## Expected Behavior

## System information

**Please complete the following information:**
-
-
MacOS 11.2.1

## Additional context

Start by reproducing the reference-wallet build on macOS 11.2.1 and inspect the build step that emits "your CLT doesn't support macos11". Determine whether the appropriate resolution is a build change or a documented workaround; done means the build path works or the required workaround is clearly documented.

Written by the indexing model from the issue text.