diff --git a/ChangeLog b/ChangeLog
index b0fa882b2c..87f992ca47 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Fri May 28 10:40:37 2010  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/mkmf.rb (checking_for): ignore toplevel.
+
 Fri May 28 00:47:16 2010  Masaya Tarui  <tarui@ruby-lnag.org>
 
 	* error.c (rb_bug): suppress the error report dialog if report_bug() 
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index 47f09f2f66..bf18f110b5 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -685,7 +685,7 @@ end
 # Internal use only.
 #
 def checking_for(m, fmt = nil)
-  f = caller[0][/in `(.*)'$/, 1] and f << ": " #` for vim #'
+  f = caller[0][/in `([^<].*)'$/, 1] and f << ": " #` for vim #'
   m = "checking #{/\Acheck/ =~ f ? '' : 'for '}#{m}... "
   message "%s", m
   a = r = nil