Gem::Ext::Builder#build_extensions

# File tmp/rubies/ruby-4.1.0-preview1/lib/rubygems/ext/builder.rb, line 325
def build_extensions
  return if @spec.extensions.empty?

  if @build_args.empty?
    say "Building native extensions. This could take a while..."
  else
    say "Building native extensions with: '#{@build_args.join " "}'"
    say "This could take a while..."
  end

  dest_path = @spec.extension_dir

  require "fileutils"
  FileUtils.rm_f @spec.gem_build_complete_path

  @spec.extensions.each do |extension|
    build_extension extension, dest_path
  end

  FileUtils.touch @spec.gem_build_complete_path
end