2 files changed, 9 insertions, 3 deletions
diff --git a/tool/eval.rb b/tool/eval.rb
index db6d11cddd..f7299c8b95 100755
--- a/tool/eval.rb
+++ b/tool/eval.rb
@@ -3,9 +3,7 @@ require 'rbconfig'
 require 'fileutils'
 require 'pp'
 
-Ruby = ENV['RUBY'] ||
-  File.join(RbConfig::CONFIG["bindir"],
-            RbConfig::CONFIG["ruby_install_name"] + RbConfig::CONFIG["EXEEXT"])
+Ruby = ENV['RUBY'] || RbConfig.ruby
 #
 
 OPTIONS = %w{
diff --git a/tool/mkconfig.rb b/tool/mkconfig.rb
index ca1f46713a..df3c35fb80 100755
--- a/tool/mkconfig.rb
+++ b/tool/mkconfig.rb
@@ -201,6 +201,14 @@ print <<EOS
   CONFIG.each_value do |val|
     RbConfig::expand(val)
   end
+
+  # returns the absolute pathname of the ruby command.
+  def RbConfig.ruby
+    File.join(
+      RbConfig::CONFIG["bindir"],
+      RbConfig::CONFIG["ruby_install_name"] + RbConfig::CONFIG["EXEEXT"]
+    )
+  end
 end
 Config = RbConfig # compatibility for ruby-1.8.4 and older.
 CROSS_COMPILING = nil unless defined? CROSS_COMPILING