readline/extconf.rb: fix typo

* ext/readline/extconf.rb: fix typo, `$defs` not `$DEFS`.
  [ruby-core:61756] [Bug #9578]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@45488 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Mon Mar 31 23:57:45 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/readline/extconf.rb: fix typo, `$defs` not `$DEFS`.
+	  [ruby-core:61756] [Bug #9578]
+
 Mon Mar 31 17:23:50 2014  NAKAMURA Usaku  <usa@ruby-lang.org>
 
 	* test/ruby/memory_status.rb: require envutil before accessing EnvUtil

ext/readline/extconf.rb

@@ -102,7 +102,7 @@ unless readline.have_type("rl_hook_func_t")
   # rl_hook_func_t is available since readline-4.2 (2001).
   # Function is removed at readline-6.3 (2014).
   # However, editline (NetBSD 6.1.3, 2014) doesn't have rl_hook_func_t.
-  $DEFS << "-Drl_hook_func_t=Function"
+  $defs << "-Drl_hook_func_t=Function"
 end
 
 create_makefile("readline")