Instructions for installing Racket and nasm in an x86 instance of Homebrew.

x86_racket_on_apple_silicon.md

Finally got around to setting up an x86 instance of Homebrew via Rosetta to install x86 Racket. Here's all the steps I took.

First, ensure Rosetta 2 is installed:

$ /usr/sbin/softwareupdate --install-rosetta

Then install x86-64 Homebrew. However, I've also kept the regular Apple Silicon Homebrew. Turns out they require different path prefixes anyway, so the regular one is at /opt/homebrew while the x86 one is at /usr/loca/homebrew. To install the x86 one, I did:

$ mkdir /tmp/homebrew
$ curl -L https://github.com/Homebrew/brew/tarball/master | tar xz -C /tmp/homebrew --strip-components=1 --
$ sudo mv /tmp/homebrew /usr/local/

I then updated my $PATH definitions so that the x86 version's bin directory has lower precedence than the Apple Silicon version's, and also created an alias so that I can still easily access the brew binary via brew64 (this is in my ~/.zprofile):

# If the x86-64 Homebrew path is found, include it first.

[[ ! -d /usr/local/homebrew ]] || {
    alias brew64="arch -x86_64 /usr/local/homebrew/bin/brew"
    export PATH="/usr/local/homebrew/bin:$PATH"
}

[[ ! -d /opt/homebrew ]] || export PATH="/opt/homebrew/bin:$PATH"

Now I can open a new (regular) terminal, and from the shell I can do type -a brew64 to see:

$ type -a brew64
brew64 is an alias for arch -x86_64 /usr/local/homebrew/bin/brew

With this, I can install nasm and Racket:

$ brew64 install nasm
$ brew64 install --cask racket

And I can confirm the x86 versions were installed:

$ file /usr/local/homebrew/bin/nasm
/usr/local/homebrew/bin/nasm: Mach-O 64-bit executable x86_64
$ file /usr/local/homebrew/bin/racket
/usr/local/homebrew/bin/racket: Mach-O 64-bit executable x86_64