Remove CLTDependency

Closes Homebrew/homebrew#29379.

Library/Homebrew/dependency_collector.rb

@@ -113,7 +113,6 @@ class DependencyCollector
     when :fortran    then FortranDependency.new(tags)
     when :mpi        then MPIDependency.new(*tags)
     when :tex        then TeXDependency.new(tags)
-    when :clt        then CLTDependency.new(tags)
     when :arch       then ArchRequirement.new(tags)
     when :hg         then MercurialDependency.new(tags)
     # python2 is deprecated
@@ -122,6 +121,7 @@ class DependencyCollector
     # Tiger's ld is too old to properly link some software
     when :ld64       then LD64Dependency.new if MacOS.version < :leopard
     when :ant        then ant_dep(spec, tags)
+    when :clt # deprecated
     else
       raise ArgumentError, "Unsupported special dependency #{spec.inspect}"
     end

Library/Homebrew/requirements.rb

@@ -67,30 +67,6 @@ class TeXDependency < Requirement
   end
 end
 
-class CLTDependency < Requirement
-  fatal true
-  build true
-
-  satisfy(:build_env => false) { MacOS::CLT.installed? }
-
-  def message
-    message = <<-EOS.undent
-      The Command Line Tools are required to compile this software.
-    EOS
-    if MacOS.version >= :mavericks
-      message += <<-EOS.undent
-        Run `xcode-select --install` to install them.
-      EOS
-    else
-      message += <<-EOS.undent
-        The standalone package can be obtained from
-        https://developer.apple.com/downloads/,
-        or it can be installed via Xcode's preferences.
-      EOS
-    end
-  end
-end
-
 class ArchRequirement < Requirement
   fatal true