All packages build from source on Rosetta

[georgio]

Output of brew config

HOMEBREW_VERSION: 4.4.13
ORIGIN: https://github.com/Homebrew/brew
HEAD: 6ea9df68df4868ce12ea7c51c85b57dce514f2e8
Last commit: 27 hours ago
Branch: stable
Core tap JSON: 24 Dec 04:01 UTC
Core cask tap JSON: 24 Dec 04:01 UTC
HOMEBREW_PREFIX: /usr/local
HOMEBREW_REPOSITORY: /usr/local/Homebrew
HOMEBREW_CELLAR: /usr/local/Cellar
HOMEBREW_CASK_OPTS: []
HOMEBREW_MAKE_JOBS: 12
Homebrew Ruby: 3.3.6 => /usr/local/Homebrew/Library/Homebrew/vendor/portable-ruby/3.3.6/bin/ruby
CPU: dodeca-core 64-bit westmere
Clang: 16.0.0 build 1600
Git: 2.39.5 => /Applications/Xcode.app/Contents/Developer/usr/bin/git
Curl: 8.7.1 => /usr/bin/curl
macOS: 15.2-x86_64
CLT: 16.2.0.0.1.1733547573
Xcode: 16.2
Rosetta 2: true

Output of 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 Homebrew's prefix is not /opt/homebrew.

Many of Homebrew's bottles (binary packages) can only be used with the default prefix.
Consider uninstalling Homebrew and reinstalling into the default prefix.
It is expected behaviour that some formulae will fail to build in this unsupported configuration.
It is expected behaviour that Homebrew will be buggy and slow.
Do not create any issues about this on Homebrew's GitHub repositories.
Do not create any issues even if you think this message is unrelated.
Any opened issues will be immediately closed without response.
Do not ask for help from Homebrew or its maintainers on social media.
You may ask for help in Homebrew's discussions but are unlikely to receive a response.
Try to figure out the problem yourself and submit a fix as a pull request.
We will review it but may or may not accept it.

Description of issue

I have 2 installations of Homebrew as indicated on your website.
The arm version works just fine.

The rosetta version is installed under /usr/local/... but the problem is that all packages for rosetta have to be built from source every time.

Is this expected behavior or am I doing something wrong?

[carlocab]

You probably need to run your Rosetta install of Homebrew under Rosetta; e.g.

arch -x86_64 /usr/local/bin/brew install ...