cpu_counter.rb: separate implementations

* lib/rake/cpu_counter.rb (Rake::CpuCounter#count): separate
  Etc.nprocessors implementation, and if is is available other
  utility methods are never used.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48279 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

lib/rake/cpu_counter.rb

@@ -1,8 +1,3 @@
-require 'rbconfig'
-
-# TODO: replace with IO.popen using array-style arguments in Rake 11
-require 'open3'
-
 module Rake
 
   # Based on a script at:
@@ -18,6 +13,26 @@ module Rake
       default
     end
 
+    begin
+      require 'etc'
+    rescue LoadError
+    else
+      if Etc.respond_to?(:nprocessors)
+        def count
+          return Etc.nprocessors
+        end
+      end
+    end
+  end
+end
+
+unless Rake::CpuCounter.method_defined?(:count)
+  Rake::CpuCounter.class_eval <<-'end;', __FILE__, __LINE__+1
+    require 'rbconfig'
+
+    # TODO: replace with IO.popen using array-style arguments in Rake 11
+    require 'open3'
+
     def count
       if defined?(Java::Java)
         count_via_java_runtime
@@ -44,18 +59,6 @@ module Rake
       end
     end
 
-    begin
-      require 'etc'
-    rescue LoadError
-    else
-      if Etc.respond_to?(:nprocessors)
-        undef count
-        def count
-          return Etc.nprocessors
-        end
-      end
-    end
-
     def count_via_java_runtime
       Java::Java.lang.Runtime.getRuntime.availableProcessors
     rescue StandardError
@@ -118,5 +121,5 @@ module Rake
         out.eof? ? nil : command
       end
     end
-  end
+  end;
 end