Use keyword

* tool/mkconfig.rb: use keyword true, instead of the toplevel
  constant.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@55615 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/mkconfig.rb

@@ -20,7 +20,7 @@ $:.unshift(".")
 require "fileutils"
 mkconfig = File.basename($0)
 
-fast = {'prefix'=>TRUE, 'ruby_install_name'=>TRUE, 'INSTALL'=>TRUE, 'EXEEXT'=>TRUE}
+fast = {'prefix'=>true, 'ruby_install_name'=>true, 'INSTALL'=>true, 'EXEEXT'=>true}
 
 win32 = /mswin/ =~ arch
 universal = /universal.*darwin/ =~ arch