Index: ext/readline/extconf.rb
===================================================================
--- ext/readline/extconf.rb	(revision 28118)
+++ ext/readline/extconf.rb	(working copy)
@@ -35,12 +35,19 @@
   have_library("termcap", "tgetnum") ||
   have_library("curses", "tgetnum")
 
-if enable_libedit
+case enable_libedit
+when true
   unless (have_readline_header("editline/readline.h") ||
           have_readline_header("readline/readline.h")) &&
           have_library("edit", "readline")
     exit
   end
+when nil
+  unless ((have_readline_header("readline/readline.h") &&
+           have_readline_header("readline/history.h")) &&
+           have_library("readline", "readline"))
+    exit
+  end
 else
   unless ((have_readline_header("readline/readline.h") &&
            have_readline_header("readline/history.h")) &&