Get Ruby stuff to compile on Apple Silicon M1

Ruby Apple Silicon M1

Here are my notes on getting the codebase to work on the new M1 processors:

Upgrade the Ruby version to 2.7.2. You may need to set some compiler flags such as:
RUBY_CFLAGS=-DUSE_FFI_CLOSURE_ALLOC rbenv install 2.7.2

Update all gems with 'bundle update'

Modify the Gemfile to detect the new hardware:
if RUBY_PLATFORM =~ /arm64.*darwin/ && `sysctl -n machdep.cpu.brand_string` =~ /M1/
  # Get things to compile for Apple Silicon - minimum Ruby version of 2.7.2
  # gem 'mini_racer', :platforms => :ruby, git: 'https://github.com/rubyjs/mini_racer.git'
  gem 'mini_racer', github: 'rubyjs/mini_racer', branch: 'refs/pull/186/head'
  gem 'ffi', '~> 1.14.2'
  gem 'pg'           # postgres
else
  gem 'therubyracer', :platforms => :ruby
  #gem 'libv8', '~> 3.21'
  gem 'pg', '~> 0.2'           # postgres
end

Gem FFI is a dependency that must be upgraded to the latest or possibly compiled with extra compiler flags like so:
gem install ffi -v '1.9.21' -- --with-cflags="-Wno-error=implicit-function-declaration"

TheRubyRacer is no longer in active development and needs to be replaced with another like MiniRacer and pulled from the main branch on Github.
https://github.com/rubyjs/mini_racer/issues/185

Another dependent gem TCLink must be linked manually to newer version of OpenSSL
gem install tclink_gs -v '4.5.0' -- --with-opt-include=$(brew --prefix openssl)/include

As always, the PG gem will likely need to be told where pg_config is. I use Postgres.app but their latest build doesn't include M1 headers. I opened a Github issue with them and they are trying to put out a new build. Meanwhile I had to use Homebrew. The command looks something like:
gem install pg --with-pg-config=/Applications/Postgres.app/Contents/Versions/9.3/bin/pg_config



https://github.com/ffi/ffi/issues/869#issuecomment-752123090
https://github.com/ffi/ffi/issues/611
https://github.com/ffi/ffi/issues/611#issuecomment-694201967