Load rubygems/platform.rb after setting up the load path

Author: nobu

ext/extmk.rb

@@ -8,8 +8,6 @@ def self.target_rbconfig
     RbConfig::CONFIG
   end
 end
-# only needs Gem::Platform
-require 'rubygems/platform'
 
 # :stopdoc:
 $extension = nil
@@ -40,6 +38,9 @@ def self.target_rbconfig
 end
 require 'rbconfig'
 
+# only needs Gem::Platform
+require 'rubygems/platform'
+
 $topdir = "."
 $top_srcdir = srcdir
 $extmk = true