include OnSystem to define DSL methods

Library/Homebrew/cask/dsl.rb

@@ -92,6 +92,7 @@ module Cask
     ]).freeze
 
     extend Predicable
+    include OnSystem
 
     attr_reader :cask, :token
 
@@ -319,8 +320,6 @@ module Cask
       @livecheckable == true
     end
 
-    OnSystem.setup_methods! onto: self, include_linux: false
-
     ORDINARY_ARTIFACT_CLASSES.each do |klass|
       define_method(klass.dsl_key) do |*args|
         if [*artifacts.map(&:class), klass].include?(Artifact::StageOnly) &&

Library/Homebrew/extend/on_system.rb

@@ -55,10 +55,10 @@ module OnSystem
     method_name.to_s.sub(/^on_/, "").to_sym
   end
 
-  sig { params(onto: Class, include_linux: T::Boolean).void }
-  def setup_methods!(onto:, include_linux: true)
+  sig { params(base: Class).void }
+  def self.included(base)
     ARCH_OPTIONS.each do |arch|
-      onto.define_method("on_#{arch}") do |&block|
+      base.define_method("on_#{arch}") do |&block|
         @on_system_blocks_exist = true
 
         return unless OnSystem.arch_condition_met? OnSystem.condition_from_method_name(__method__)
@@ -71,9 +71,8 @@ module OnSystem
       end
     end
 
-    if include_linux
     BASE_OS_OPTIONS.each do |base_os|
-        onto.define_method("on_#{base_os}") do |&block|
+      base.define_method("on_#{base_os}") do |&block|
         @on_system_blocks_exist = true
 
         return unless OnSystem.os_condition_met? OnSystem.condition_from_method_name(__method__)
@@ -85,10 +84,9 @@ module OnSystem
         result
       end
     end
-    end
 
     MacOSVersions::SYMBOLS.each_key do |os_name|
-      onto.define_method("on_#{os_name}") do |or_condition = nil, &block|
+      base.define_method("on_#{os_name}") do |or_condition = nil, &block|
         @on_system_blocks_exist = true
 
         os_condition = OnSystem.condition_from_method_name __method__

Library/Homebrew/formula.rb

@@ -64,12 +64,11 @@ class Formula
   include Utils::Shebang
   include Utils::Shell
   include Context
+  include OnSystem
   extend Forwardable
   extend Cachable
   extend Predicable
 
-  OnSystem.setup_methods! onto: self
-
   # @!method inreplace(paths, before = nil, after = nil)
   # @see Utils::Inreplace.inreplace
 
@@ -2471,6 +2470,7 @@ class Formula
   # The methods below define the formula DSL.
   class << self
     include BuildEnvironment::DSL
+    include OnSystem
 
     def method_added(method)
       super
@@ -2483,8 +2483,6 @@ class Formula
       end
     end
 
-    OnSystem.setup_methods! onto: self
-
     # The reason for why this software is not linked (by default) to
     # {::HOMEBREW_PREFIX}.
     # @private

Library/Homebrew/resource.rb

@@ -17,8 +17,7 @@ class Resource
 
   include Context
   include FileUtils
-
-  OnSystem.setup_methods! onto: self
+  include OnSystem
 
   attr_reader :mirrors, :specs, :using, :source_modified_time, :patches, :owner
   attr_writer :version

Library/Homebrew/software_spec.rb

@@ -18,14 +18,13 @@ class SoftwareSpec
   extend T::Sig
 
   extend Forwardable
+  include OnSystem
 
   PREDEFINED_OPTIONS = {
     universal: Option.new("universal", "Build a universal binary"),
     cxx11:     Option.new("c++11",     "Build using C++11 mode"),
   }.freeze
 
-  OnSystem.setup_methods! onto: self
-
   attr_reader :name, :full_name, :owner, :build, :resources, :patches, :options, :deprecated_flags,
               :deprecated_options, :dependency_collector, :bottle_specification, :compiler_failures,
               :uses_from_macos_elements
@@ -584,7 +583,7 @@ class BottleSpecification
 end
 
 class PourBottleCheck
-  OnSystem.setup_methods! onto: self
+  include OnSystem
 
   def initialize(formula)
     @formula = formula