Move MacOS modules under OS::Mac namespace

Closes Homebrew/homebrew#23138.

4 files changed, 349 insertions, 333 deletions

diff --git a/Library/Homebrew/os/mac.rb b/Library/Homebrew/os/mac.rb
index d4e8e722b..832f3f52b 100644
--- a/Library/Homebrew/os/mac.rb
+++ b/Library/Homebrew/os/mac.rb
@@ -1,5 +1,7 @@
 require 'hardware'
 require 'os/mac/version'
+require 'os/mac/xcode'
+require 'os/mac/xquartz'
 
 module OS
   module Mac
@@ -270,6 +272,3 @@ module OS
     end
   end
 end
-
-require 'os/mac/xcode'
-require 'os/mac/xquartz'
diff --git a/Library/Homebrew/os/mac/version.rb b/Library/Homebrew/os/mac/version.rb
index 4de3b91e7..cfe42a75f 100644
--- a/Library/Homebrew/os/mac/version.rb
+++ b/Library/Homebrew/os/mac/version.rb
@@ -1,39 +1,41 @@
 require 'version'
 
-module MacOS
-  class Version < ::Version
-    SYMBOLS = {
-      :mavericks     => '10.9',
-      :mountain_lion => '10.8',
-      :lion          => '10.7',
-      :snow_leopard  => '10.6',
-      :leopard       => '10.5',
-      :tiger         => '10.4',
-    }
+module OS
+  module Mac
+    class Version < ::Version
+      SYMBOLS = {
+        :mavericks     => '10.9',
+        :mountain_lion => '10.8',
+        :lion          => '10.7',
+        :snow_leopard  => '10.6',
+        :leopard       => '10.5',
+        :tiger         => '10.4',
+      }
 
-    def self.from_symbol(sym)
-      new(SYMBOLS.fetch(sym))
-    end
+      def self.from_symbol(sym)
+        new(SYMBOLS.fetch(sym))
+      end
 
-    def <=>(other)
-      v = SYMBOLS.fetch(other, other.to_s)
-      super(Version.new(v))
-    end
+      def <=>(other)
+        v = SYMBOLS.fetch(other, other.to_s)
+        super(Version.new(v))
+      end
 
-    def to_sym
-      case @version
-      when '10.9' then :mavericks
-      when '10.8' then :mountain_lion
-      when '10.7' then :lion
-      when '10.6' then :snow_leopard
-      when '10.5' then :leopard
-      when '10.4' then :tiger
-      else :dunno
+      def to_sym
+        case @version
+        when '10.9' then :mavericks
+        when '10.8' then :mountain_lion
+        when '10.7' then :lion
+        when '10.6' then :snow_leopard
+        when '10.5' then :leopard
+        when '10.4' then :tiger
+        else :dunno
+        end
       end
-    end
 
-    def pretty_name
-      to_sym.to_s.split('_').map(&:capitalize).join(' ')
+      def pretty_name
+        to_sym.to_s.split('_').map(&:capitalize).join(' ')
+      end
     end
   end
 end
diff --git a/Library/Homebrew/os/mac/xcode.rb b/Library/Homebrew/os/mac/xcode.rb
index 0472f73ab..843b3dd61 100644
--- a/Library/Homebrew/os/mac/xcode.rb
+++ b/Library/Homebrew/os/mac/xcode.rb
@@ -1,203 +1,210 @@
-module MacOS::Xcode extend self
-
-  V4_BUNDLE_ID = "com.apple.dt.Xcode"
-  V3_BUNDLE_ID = "com.apple.Xcode"
-  V4_BUNDLE_PATH = Pathname.new("/Applications/Xcode.app")
-  V3_BUNDLE_PATH = Pathname.new("/Developer/Applications/Xcode.app")
-
-  # Locate the "current Xcode folder" via xcode-select. See:
-  # man xcode-select
-  # NOTE!! use Xcode.prefix rather than this generally!
-  def folder
-    @folder ||= `xcode-select -print-path 2>/dev/null`.strip
-  end
+module OS
+  module Mac
+    module Xcode
+      extend self
+
+      V4_BUNDLE_ID = "com.apple.dt.Xcode"
+      V3_BUNDLE_ID = "com.apple.Xcode"
+      V4_BUNDLE_PATH = Pathname.new("/Applications/Xcode.app")
+      V3_BUNDLE_PATH = Pathname.new("/Developer/Applications/Xcode.app")
+
+      # Locate the "current Xcode folder" via xcode-select. See:
+      # man xcode-select
+      # NOTE!! use Xcode.prefix rather than this generally!
+      def folder
+        @folder ||= `xcode-select -print-path 2>/dev/null`.strip
+      end
 
-  # Xcode 4.3 tools hang if "/" is set
-  def bad_xcode_select_path?
-    folder == "/"
-  end
+      # Xcode 4.3 tools hang if "/" is set
+      def bad_xcode_select_path?
+        folder == "/"
+      end
 
-  def latest_version
-    case MacOS.version
-    when "10.4"         then "2.5"
-    when "10.5"         then "3.1.4"
-    when "10.6"         then "3.2.6"
-    when "10.7"         then "4.6.3"
-    when "10.8"         then "5.0"
-    when "10.9"         then "5.0.1"
-    else
-      # Default to newest known version of Xcode for unreleased OSX versions.
-      if MacOS.version > 10.9
-        "5.0.1"
-      else
-        raise "Mac OS X '#{MacOS.version}' is invalid"
+      def latest_version
+        case MacOS.version
+        when "10.4"         then "2.5"
+        when "10.5"         then "3.1.4"
+        when "10.6"         then "3.2.6"
+        when "10.7"         then "4.6.3"
+        when "10.8"         then "5.0"
+        when "10.9"         then "5.0.1"
+        else
+          # Default to newest known version of Xcode for unreleased OSX versions.
+          if MacOS.version > 10.9
+            "5.0.1"
+          else
+            raise "Mac OS X '#{MacOS.version}' is invalid"
+          end
+        end
       end
-    end
-  end
 
-  def outdated?
-    version < latest_version
-  end
+      def outdated?
+        version < latest_version
+      end
 
-  def without_clt?
-    installed? && version >= "4.3" && !MacOS::CLT.installed?
-  end
+      def without_clt?
+        installed? && version >= "4.3" && !MacOS::CLT.installed?
+      end
 
-  def prefix
-    @prefix ||= begin
-      path = Pathname.new(folder)
-      if path.absolute? and File.executable? "#{path}/usr/bin/make"
-        path
-      elsif File.executable? '/Developer/usr/bin/make'
-        # we do this to support cowboys who insist on installing
-        # only a subset of Xcode
-        Pathname.new('/Developer')
-      elsif File.executable? "#{V4_BUNDLE_PATH}/Contents/Developer/usr/bin/make"
-        # fallback for broken Xcode 4.3 installs
-        Pathname.new("#{V4_BUNDLE_PATH}/Contents/Developer")
-      elsif (path = bundle_path)
-        path += "Contents/Developer"
-        path if File.executable? "#{path}/usr/bin/make"
+      def prefix
+        @prefix ||= begin
+          path = Pathname.new(folder)
+          if path.absolute? and File.executable? "#{path}/usr/bin/make"
+            path
+          elsif File.executable? '/Developer/usr/bin/make'
+            # we do this to support cowboys who insist on installing
+            # only a subset of Xcode
+            Pathname.new('/Developer')
+          elsif File.executable? "#{V4_BUNDLE_PATH}/Contents/Developer/usr/bin/make"
+            # fallback for broken Xcode 4.3 installs
+            Pathname.new("#{V4_BUNDLE_PATH}/Contents/Developer")
+          elsif (path = bundle_path)
+            path += "Contents/Developer"
+            path if File.executable? "#{path}/usr/bin/make"
+          end
+        end
       end
-    end
-  end
 
-  # Ask Spotlight where Xcode is. If the user didn't install the
-  # helper tools and installed Xcode in a non-conventional place, this
-  # is our only option. See: http://superuser.com/questions/390757
-  def bundle_path
-    MacOS.app_with_bundle_id(V4_BUNDLE_ID) || MacOS.app_with_bundle_id(V3_BUNDLE_ID)
-  end
+      # Ask Spotlight where Xcode is. If the user didn't install the
+      # helper tools and installed Xcode in a non-conventional place, this
+      # is our only option. See: http://superuser.com/questions/390757
+      def bundle_path
+        MacOS.app_with_bundle_id(V4_BUNDLE_ID) || MacOS.app_with_bundle_id(V3_BUNDLE_ID)
+      end
 
-  def installed?
-    not prefix.nil?
-  end
+      def installed?
+        not prefix.nil?
+      end
 
-  def version
-    # may return a version string
-    # that is guessed based on the compiler, so do not
-    # use it in order to check if Xcode is installed.
-    @version ||= uncached_version
-  end
+      def version
+        # may return a version string
+        # that is guessed based on the compiler, so do not
+        # use it in order to check if Xcode is installed.
+        @version ||= uncached_version
+      end
 
-  def uncached_version
-    # This is a separate function as you can't cache the value out of a block
-    # if return is used in the middle, which we do many times in here.
+      def uncached_version
+        # This is a separate function as you can't cache the value out of a block
+        # if return is used in the middle, which we do many times in here.
+
+        return "0" unless OS.mac?
+
+        # this shortcut makes version work for people who don't realise you
+        # need to install the CLI tools
+        xcode43build = Pathname.new("#{prefix}/usr/bin/xcodebuild")
+        if xcode43build.file?
+          `#{xcode43build} -version 2>/dev/null` =~ /Xcode (\d(\.\d)*)/
+          return $1 if $1
+        end
+
+        # Xcode 4.3 xc* tools hang indefinately if xcode-select path is set thus
+        raise if bad_xcode_select_path?
+
+        raise unless which "xcodebuild"
+        `xcodebuild -version 2>/dev/null` =~ /Xcode (\d(\.\d)*)/
+        raise if $1.nil? or not $?.success?
+        $1
+      rescue
+        # For people who's xcode-select is unset, or who have installed
+        # xcode-gcc-installer or whatever other combinations we can try and
+        # supprt. See https://github.com/mxcl/homebrew/wiki/Xcode
+        case MacOS.llvm_build_version.to_i
+        when 1..2063 then "3.1.0"
+        when 2064..2065 then "3.1.4"
+        when 2366..2325
+          # we have no data for this range so we are guessing
+          "3.2.0"
+        when 2326
+          # also applies to "3.2.3"
+          "3.2.4"
+        when 2327..2333 then "3.2.5"
+        when 2335
+          # this build number applies to 3.2.6, 4.0 and 4.1
+          # https://github.com/mxcl/homebrew/wiki/Xcode
+          "4.0"
+        else
+          case (MacOS.clang_version.to_f * 10).to_i
+          when 0       then "dunno"
+          when 1..14   then "3.2.2"
+          when 15      then "3.2.4"
+          when 16      then "3.2.5"
+          when 17..20  then "4.0"
+          when 21      then "4.1"
+          when 22..30  then "4.2"
+          when 31      then "4.3"
+          when 40      then "4.4"
+          when 41      then "4.5"
+          when 42      then "4.6"
+          when 50      then "5.0"
+          else "4.6"
+          end
+        end
+      end
 
-    return "0" unless OS.mac?
+      def provides_autotools?
+        version.to_f < 4.3
+      end
 
-    # this shortcut makes version work for people who don't realise you
-    # need to install the CLI tools
-    xcode43build = Pathname.new("#{prefix}/usr/bin/xcodebuild")
-    if xcode43build.file?
-      `#{xcode43build} -version 2>/dev/null` =~ /Xcode (\d(\.\d)*)/
-      return $1 if $1
-    end
+      def provides_gcc?
+        version.to_f < 4.3
+      end
 
-    # Xcode 4.3 xc* tools hang indefinately if xcode-select path is set thus
-    raise if bad_xcode_select_path?
-
-    raise unless which "xcodebuild"
-    `xcodebuild -version 2>/dev/null` =~ /Xcode (\d(\.\d)*)/
-    raise if $1.nil? or not $?.success?
-    $1
-  rescue
-    # For people who's xcode-select is unset, or who have installed
-    # xcode-gcc-installer or whatever other combinations we can try and
-    # supprt. See https://github.com/mxcl/homebrew/wiki/Xcode
-    case MacOS.llvm_build_version.to_i
-    when 1..2063 then "3.1.0"
-    when 2064..2065 then "3.1.4"
-    when 2366..2325
-      # we have no data for this range so we are guessing
-      "3.2.0"
-    when 2326
-      # also applies to "3.2.3"
-      "3.2.4"
-    when 2327..2333 then "3.2.5"
-    when 2335
-      # this build number applies to 3.2.6, 4.0 and 4.1
-      # https://github.com/mxcl/homebrew/wiki/Xcode
-      "4.0"
-    else
-      case (MacOS.clang_version.to_f * 10).to_i
-      when 0       then "dunno"
-      when 1..14   then "3.2.2"
-      when 15      then "3.2.4"
-      when 16      then "3.2.5"
-      when 17..20  then "4.0"
-      when 21      then "4.1"
-      when 22..30  then "4.2"
-      when 31      then "4.3"
-      when 40      then "4.4"
-      when 41      then "4.5"
-      when 42      then "4.6"
-      when 50      then "5.0"
-      else "4.6"
+      def default_prefix?
+        if version.to_f < 4.3
+          %r{^/Developer} === prefix
+        else
+          %r{^/Applications/Xcode.app} === prefix
+        end
       end
     end
-  end
 
-  def provides_autotools?
-    version.to_f < 4.3
-  end
+    module CLT
+      extend self
 
-  def provides_gcc?
-    version.to_f < 4.3
-  end
+      STANDALONE_PKG_ID = "com.apple.pkg.DeveloperToolsCLILeo"
+      FROM_XCODE_PKG_ID = "com.apple.pkg.DeveloperToolsCLI"
+      STANDALONE_PKG_PATH = Pathname.new("/Library/Developer/CommandLineTools")
 
-  def default_prefix?
-    if version.to_f < 4.3
-      %r{^/Developer} === prefix
-    else
-      %r{^/Applications/Xcode.app} === prefix
-    end
-  end
-end
-
-module MacOS::CLT extend self
-  STANDALONE_PKG_ID = "com.apple.pkg.DeveloperToolsCLILeo"
-  FROM_XCODE_PKG_ID = "com.apple.pkg.DeveloperToolsCLI"
-  STANDALONE_PKG_PATH = Pathname.new("/Library/Developer/CommandLineTools")
-
-  # True if:
-  #  - Xcode < 4.3 is installed. The tools are found under /usr.
-  #  - The "Command Line Tools" package has been installed
-  #    For OS X < 10.9, the tools are found under /usr. For 10.9,
-  #    they are found under /Library/Developer/CommandLineTools.
-  def installed?
-    mavericks_dev_tools? || usr_dev_tools?
-  end
+      # True if:
+      #  - Xcode < 4.3 is installed. The tools are found under /usr.
+      #  - The "Command Line Tools" package has been installed
+      #    For OS X < 10.9, the tools are found under /usr. For 10.9,
+      #    they are found under /Library/Developer/CommandLineTools.
+      def installed?
+        mavericks_dev_tools? || usr_dev_tools?
+      end
 
-  def mavericks_dev_tools?
-    MacOS.dev_tools_path == Pathname("#{STANDALONE_PKG_PATH}/usr/bin") &&
-      File.directory?("#{STANDALONE_PKG_PATH}/usr/include")
-  end
+      def mavericks_dev_tools?
+        MacOS.dev_tools_path == Pathname("#{STANDALONE_PKG_PATH}/usr/bin") &&
+          File.directory?("#{STANDALONE_PKG_PATH}/usr/include")
+      end
 
-  def usr_dev_tools?
-    MacOS.dev_tools_path == Pathname("/usr/bin") && File.directory?("/usr/include")
-  end
+      def usr_dev_tools?
+        MacOS.dev_tools_path == Pathname("/usr/bin") && File.directory?("/usr/include")
+      end
 
-  def latest_version?
-    `/usr/bin/clang --version` =~ %r{clang-(\d+)\.(\d+)\.(\d+)}
-    $1.to_i >= 425 and $3.to_i >= 28
-  end
+      def latest_version?
+        `/usr/bin/clang --version` =~ %r{clang-(\d+)\.(\d+)\.(\d+)}
+        $1.to_i >= 425 and $3.to_i >= 28
+      end
 
-  def outdated?
-    !latest_version?
-  end
+      def outdated?
+        !latest_version?
+      end
 
-  # Version string (a pretty damn long one) of the CLT package.
-  # Note, that different ways to install the CLTs lead to different
-  # version numbers.
-  def version
-    @version ||= detect_version
-  end
+      # Version string (a pretty damn long one) of the CLT package.
+      # Note, that different ways to install the CLTs lead to different
+      # version numbers.
+      def version
+        @version ||= detect_version
+      end
 
-  def detect_version
-    [STANDALONE_PKG_ID, FROM_XCODE_PKG_ID].find do |id|
-      version = MacOS.pkgutil_info(id)[/version: (.+)$/, 1]
-      return version if version
+      def detect_version
+        [STANDALONE_PKG_ID, FROM_XCODE_PKG_ID].find do |id|
+          version = MacOS.pkgutil_info(id)[/version: (.+)$/, 1]
+          return version if version
+        end
+      end
     end
   end
 end
diff --git a/Library/Homebrew/os/mac/xquartz.rb b/Library/Homebrew/os/mac/xquartz.rb
index 418550aa8..82680d3ba 100644
--- a/Library/Homebrew/os/mac/xquartz.rb
+++ b/Library/Homebrew/os/mac/xquartz.rb
@@ -1,131 +1,139 @@
-module MacOS::XQuartz extend self
-  FORGE_BUNDLE_ID = "org.macosforge.xquartz.X11"
-  APPLE_BUNDLE_ID = "org.x.X11"
-  FORGE_PKG_ID = "org.macosforge.xquartz.pkg"
-
-  PKGINFO_VERSION_MAP = {
-    "2.6.34" => "2.6.3",
-    "2.7.4"  => "2.7.0",
-    "2.7.14" => "2.7.1",
-    "2.7.28" => "2.7.2",
-    "2.7.32" => "2.7.3",
-    "2.7.43" => "2.7.4",
-    "2.7.50" => "2.7.5_rc1",
-    "2.7.51" => "2.7.5_rc2",
-  }.freeze
-
-  # This returns the version number of XQuartz, not of the upstream X.org.
-  # The X11.app distributed by Apple is also XQuartz, and therefore covered
-  # by this method.
-  def version
-    @version ||= detect_version
-  end
-
-  def detect_version
-    if (path = bundle_path) && path.exist? && (version = version_from_mdls(path))
-      version
-    elsif prefix.to_s == "/usr/X11"
-      guess_system_version
-    else
-      version_from_pkgutil
-    end
-  end
-
-  def latest_version
-    "2.7.4"
-  end
-
-  def bundle_path
-    MacOS.app_with_bundle_id(FORGE_BUNDLE_ID) || MacOS.app_with_bundle_id(APPLE_BUNDLE_ID)
-  end
-
-  def version_from_mdls(path)
-    version = `mdls -raw -nullMarker "" -name kMDItemVersion "#{path}" 2>/dev/null`.strip
-    version unless version.empty?
-  end
-
-  # The XQuartz that Apple shipped in OS X through 10.7 does not have a
-  # pkg-util entry, so if Spotlight indexing is disabled we must make an
-  # educated guess as to what version is installed.
-  def guess_system_version
-    case MacOS.version
-    when '10.5' then '2.1.6'
-    when '10.6' then '2.3.6'
-    when '10.7' then '2.6.3'
-    else 'dunno'
-    end
-  end
-
-  # Upstream XQuartz *does* have a pkg-info entry, so if we can't get it
-  # from mdls, we can try pkgutil. This is very slow.
-  def version_from_pkgutil
-    str = MacOS.pkgutil_info(FORGE_PKG_ID)[/version: (\d\.\d\.\d+)$/, 1]
-    PKGINFO_VERSION_MAP.fetch(str, str)
-  end
-
-  def provided_by_apple?
-    [FORGE_BUNDLE_ID, APPLE_BUNDLE_ID].find do |id|
-      MacOS.app_with_bundle_id(id)
-    end == APPLE_BUNDLE_ID
-  end
-
-  # This should really be private, but for compatibility reasons it must
-  # remain public. New code should use MacOS::X11.{bin,lib,include}
-  # instead, as that accounts for Xcode-only systems.
-  def prefix
-    @prefix ||= if Pathname.new('/opt/X11/lib/libpng.dylib').exist?
-      Pathname.new('/opt/X11')
-    elsif Pathname.new('/usr/X11/lib/libpng.dylib').exist?
-      Pathname.new('/usr/X11')
+module OS
+  module Mac
+    module XQuartz
+      extend self
+
+      FORGE_BUNDLE_ID = "org.macosforge.xquartz.X11"
+      APPLE_BUNDLE_ID = "org.x.X11"
+      FORGE_PKG_ID = "org.macosforge.xquartz.pkg"
+
+      PKGINFO_VERSION_MAP = {
+        "2.6.34" => "2.6.3",
+        "2.7.4"  => "2.7.0",
+        "2.7.14" => "2.7.1",
+        "2.7.28" => "2.7.2",
+        "2.7.32" => "2.7.3",
+        "2.7.43" => "2.7.4",
+        "2.7.50" => "2.7.5_rc1",
+        "2.7.51" => "2.7.5_rc2",
+      }.freeze
+
+      # This returns the version number of XQuartz, not of the upstream X.org.
+      # The X11.app distributed by Apple is also XQuartz, and therefore covered
+      # by this method.
+      def version
+        @version ||= detect_version
+      end
+
+      def detect_version
+        if (path = bundle_path) && path.exist? && (version = version_from_mdls(path))
+          version
+        elsif prefix.to_s == "/usr/X11"
+          guess_system_version
+        else
+          version_from_pkgutil
+        end
+      end
+
+      def latest_version
+        "2.7.4"
+      end
+
+      def bundle_path
+        MacOS.app_with_bundle_id(FORGE_BUNDLE_ID) || MacOS.app_with_bundle_id(APPLE_BUNDLE_ID)
+      end
+
+      def version_from_mdls(path)
+        version = `mdls -raw -nullMarker "" -name kMDItemVersion "#{path}" 2>/dev/null`.strip
+        version unless version.empty?
+      end
+
+      # The XQuartz that Apple shipped in OS X through 10.7 does not have a
+      # pkg-util entry, so if Spotlight indexing is disabled we must make an
+      # educated guess as to what version is installed.
+      def guess_system_version
+        case MacOS.version
+        when '10.5' then '2.1.6'
+        when '10.6' then '2.3.6'
+        when '10.7' then '2.6.3'
+        else 'dunno'
+        end
+      end
+
+      # Upstream XQuartz *does* have a pkg-info entry, so if we can't get it
+      # from mdls, we can try pkgutil. This is very slow.
+      def version_from_pkgutil
+        str = MacOS.pkgutil_info(FORGE_PKG_ID)[/version: (\d\.\d\.\d+)$/, 1]
+        PKGINFO_VERSION_MAP.fetch(str, str)
+      end
+
+      def provided_by_apple?
+        [FORGE_BUNDLE_ID, APPLE_BUNDLE_ID].find do |id|
+          MacOS.app_with_bundle_id(id)
+        end == APPLE_BUNDLE_ID
+      end
+
+      # This should really be private, but for compatibility reasons it must
+      # remain public. New code should use MacOS::X11.{bin,lib,include}
+      # instead, as that accounts for Xcode-only systems.
+      def prefix
+        @prefix ||= if Pathname.new('/opt/X11/lib/libpng.dylib').exist?
+          Pathname.new('/opt/X11')
+        elsif Pathname.new('/usr/X11/lib/libpng.dylib').exist?
+          Pathname.new('/usr/X11')
+        end
+      end
+
+      def installed?
+        !version.nil? && !prefix.nil?
+      end
     end
-  end
-
-  def installed?
-    !version.nil? && !prefix.nil?
-  end
-end
-
-module MacOS::X11 extend self
-  def prefix
-    MacOS::XQuartz.prefix
-  end
-
-  def installed?
-    MacOS::XQuartz.installed?
-  end
-
-  # If XQuartz and/or the CLT are installed, headers will be found under
-  # /opt/X11/include or /usr/X11/include. For Xcode-only systems, they are
-  # found in the SDK, so we use sdk_path for both the headers and libraries.
-  # Confusingly, executables (e.g. config scripts) are only found under
-  # /opt/X11/bin or /usr/X11/bin in all cases.
-  def bin
-    Pathname.new("#{prefix}/bin")
-  end
 
-  def include
-    @include ||= if use_sdk?
-      Pathname.new("#{MacOS.sdk_path}/usr/X11/include")
-    else
-      Pathname.new("#{prefix}/include")
+    module X11
+      extend self
+
+      def prefix
+        MacOS::XQuartz.prefix
+      end
+
+      def installed?
+        MacOS::XQuartz.installed?
+      end
+
+      # If XQuartz and/or the CLT are installed, headers will be found under
+      # /opt/X11/include or /usr/X11/include. For Xcode-only systems, they are
+      # found in the SDK, so we use sdk_path for both the headers and libraries.
+      # Confusingly, executables (e.g. config scripts) are only found under
+      # /opt/X11/bin or /usr/X11/bin in all cases.
+      def bin
+        Pathname.new("#{prefix}/bin")
+      end
+
+      def include
+        @include ||= if use_sdk?
+          Pathname.new("#{MacOS.sdk_path}/usr/X11/include")
+        else
+          Pathname.new("#{prefix}/include")
+        end
+      end
+
+      def lib
+        @lib ||= if use_sdk?
+          Pathname.new("#{MacOS.sdk_path}/usr/X11/lib")
+        else
+          Pathname.new("#{prefix}/lib")
+        end
+      end
+
+      def share
+        Pathname.new("#{prefix}/share")
+      end
+
+      private
+
+      def use_sdk?
+        not (prefix.to_s == '/opt/X11' or MacOS::CLT.installed?)
+      end
     end
   end
-
-  def lib
-    @lib ||= if use_sdk?
-      Pathname.new("#{MacOS.sdk_path}/usr/X11/lib")
-    else
-      Pathname.new("#{prefix}/lib")
-    end
-  end
-
-  def share
-    Pathname.new("#{prefix}/share")
-  end
-
-  private
-
-  def use_sdk?
-    not (prefix.to_s == '/opt/X11' or MacOS::CLT.installed?)
-  end
 end