Avoid comparing Xcode.version to floats

Library/Homebrew/cmd/--config.rb

@@ -42,7 +42,7 @@ module Homebrew extend self
   def clt
     if instance_variable_defined?(:@clt)
       @clt
-    elsif MacOS::CLT.installed? && MacOS::Xcode.version.to_f >= 4.3
+    elsif MacOS::CLT.installed? && MacOS::Xcode.version >= "4.3"
       @clt = MacOS::CLT.version
     end
   end

Library/Homebrew/os/mac/xcode.rb

@@ -143,15 +143,15 @@ module OS
       end
 
       def provides_autotools?
-        version.to_f < 4.3
+        version < "4.3"
       end
 
       def provides_gcc?
-        version.to_f < 4.3
+        version < "4.3"
       end
 
       def default_prefix?
-        if version.to_f < 4.3
+        if version < "4.3"
           %r{^/Developer} === prefix
         else
           %r{^/Applications/Xcode.app} === prefix