Make fails_with available in spec blocks

Closes Homebrew/homebrew#31706.

Library/Homebrew/formula.rb

@@ -3,7 +3,6 @@ require 'formula_lock'
 require 'formula_pin'
 require 'hardware'
 require 'bottles'
-require 'compilers'
 require 'build_environment'
 require 'build_options'
 require 'formulary'
@@ -111,6 +110,10 @@ class Formula
     active_spec.option_defined?(name)
   end
 
+  def fails_with?(compiler)
+    active_spec.fails_with?(compiler)
+  end
+
   # if the dir is there, but it's empty we consider it not installed
   def installed?
     (dir = installed_prefix).directory? && dir.children.length > 0
@@ -228,10 +231,6 @@ class Formula
     self.class.keg_only_reason
   end
 
-  def fails_with? compiler
-    (self.class.cc_failures || []).any? { |failure| failure === compiler }
-  end
-
   # sometimes the formula cleaner breaks things
   # skip cleaning paths in a formula with a class method like this:
   #   skip_clean "bin/foo", "lib"bar"
@@ -609,7 +608,7 @@ class Formula
   class << self
     include BuildEnvironmentDSL
 
-    attr_reader :keg_only_reason, :cc_failures
+    attr_reader :keg_only_reason
     attr_rw :homepage, :plist_startup, :plist_manual, :revision
 
     def specs
@@ -742,16 +741,12 @@ class Formula
     # fails_with :gcc => '4.8' do
     #   version '4.8.1'
     # end
-    def fails_with spec, &block
-      @cc_failures ||= Set.new
-      @cc_failures << CompilerFailure.create(spec, &block)
+    def fails_with compiler, &block
+      specs.each { |spec| spec.fails_with(compiler, &block) }
     end
 
     def needs *standards
-      @cc_failures ||= Set.new
-      standards.each do |standard|
-        @cc_failures.merge CompilerFailure.for_standard standard
-      end
+      specs.each { |spec| spec.needs(*standards) }
     end
 
     def test &block

Library/Homebrew/software_spec.rb

@@ -7,6 +7,7 @@ require 'build_options'
 require 'dependency_collector'
 require 'bottles'
 require 'patch'
+require 'compilers'
 
 class SoftwareSpec
   extend Forwardable
@@ -21,6 +22,7 @@ class SoftwareSpec
   attr_reader :build, :resources, :patches, :options
   attr_reader :dependency_collector
   attr_reader :bottle_specification
+  attr_reader :compiler_failures
 
   def_delegators :@resource, :stage, :fetch, :verify_download_integrity
   def_delegators :@resource, :cached_download, :clear_cache
@@ -35,6 +37,7 @@ class SoftwareSpec
     @patches = []
     @options = Options.new
     @build = BuildOptions.new(Options.create(ARGV.options_only), options)
+    @compiler_failures = []
   end
 
   def owner= owner
@@ -112,6 +115,20 @@ class SoftwareSpec
     patches << Patch.create(strip, src, &block)
   end
 
+  def fails_with? compiler
+    compiler_failures.any? { |failure| failure === compiler }
+  end
+
+  def fails_with compiler, &block
+    compiler_failures << CompilerFailure.create(compiler, &block)
+  end
+
+  def needs *standards
+    standards.each do |standard|
+      compiler_failures.concat CompilerFailure.for_standard(standard)
+    end
+  end
+
   def add_legacy_patches(list)
     list = Patch.normalize_legacy_patches(list)
     list.each { |p| p.owner = self }