Do not copy platform/version dependent file to independent path

Rakefile

@@ -10,7 +10,22 @@ Rake::TestTask.new(:test) do |t|
 end
 
 require 'rake/extensiontask'
-Rake::ExtensionTask.new(name)
+class << Rake::ExtensionTask.new(name)
+  def evil_copy?(src, dest)
+    version = %r[/\d+(?:\.\d+){1,2}/]
+    src.include?(platform) and version =~ src and !(dest.include?(platform) and version =~ dest)
+  end
+
+  def install(src, dest, **)
+    return if evil_copy?(src, dest)
+    super
+  end
+  def cp(src, dest, **)
+    return if evil_copy?(src, dest)
+    super
+  end
+end
+
 task :test => :compile
 
 task :default => :test