I previously added the 8 curl exit code (weird server reply) to the
list of non-success exit codes that `#curl_headers` will handle.
We're now seeing failures with a 56 exit code (failure in receiving
network data), where the server returns a 4xx response for a `HEAD`
request but the same request using `GET` works as expected (e.g.,
casks like `beeper`, `get-api`, `odrive`, `ui`, etc.).
This adds 56 to the list of exit codes in `#curl_headers`, so a
response with a 4xx HTTP status will be automatically retried using
`GET`.
- Avoid near duplicate messages
- Provide correct CLT download instructions
Before:
```
$ brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!
Warning: Your Command Line Tools are too outdated.
Update them from Software Update in System Settings.
If that doesn't show you any updates, run:
sudo rm -rf /Library/Developer/CommandLineTools
sudo xcode-select --install
Alternatively, manually download them from:
https://developer.apple.com/download/all/.
You should download the Command Line Tools for Xcode 16.0.
Warning: A newer Command Line Tools release is available.
Update them from Software Update in System Settings.
If that doesn't show you any updates, run:
sudo rm -rf /Library/Developer/CommandLineTools
sudo xcode-select --install
Alternatively, manually download them from:
https://developer.apple.com/download/all/.
You should download the Command Line Tools for Xcode 16.0.
Warning: Your Xcode (15.4) at /Applications/Xcode.app is too outdated.
Please update to Xcode 16.0 (or delete it).
Xcode can be updated from:
https://developer.apple.com/download/all/
Warning: Your Xcode (15.4) is outdated.
Please update to Xcode 16.0 (or delete it).
Xcode can be updated from:
https://developer.apple.com/download/all/
If 16.0 is installed, you may need to:
sudo xcode-select --switch /Applications/Xcode.app
Current developer directory is:
/Applications/Xcode.app/Contents/Developer
```
After:
```console
$ brew doctor
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry or file an issue; just ignore this. Thanks!
Warning: Your Command Line Tools are too outdated.
Install the Command Line Tools for Xcode 16 from:
https://developer.apple.com/download/all/
Warning: Your Xcode (15.4) at /Applications/Xcode.app is too outdated.
Please update to Xcode 16.0 (or delete it).
Xcode can be updated from:
https://developer.apple.com/download/all/
```
