diff --git a/ChangeLog b/ChangeLog
index d169520c60..7965d343cd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+Tue Dec 18 01:40:20 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* lib/mkmf.rb (depend_rules): inserts ruby to only headers.
+
 Tue Dec 18 01:21:19 2007  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* parse.y (parser_encode_length): chomp eol style modifiers.
diff --git a/lib/mkmf.rb b/lib/mkmf.rb
index aedb376e5c..2c1016da8f 100644
--- a/lib/mkmf.rb
+++ b/lib/mkmf.rb
@@ -1299,7 +1299,7 @@ def depend_rules(depend)
   depend.each_line do |line|
     line.gsub!(/\.o\b/, ".#{$OBJEXT}")
     line.gsub!(/\$\((?:hdr|top)dir\)\/config.h/, $config_h) if $config_h
-    line.gsub!(%r"\$\(hdrdir\)/(?!ruby(?![^:;/\s]))", '\&ruby/') if /^\s*\w+\s*=/ !~ line
+    line.gsub!(%r"\$\(hdrdir\)/(?!ruby(?![^:;/\s]))(?=[-\w]+\.h)", '\&ruby/')
     if /(?:^|[^\\])(?:\\\\)*\\$/ =~ line
       (cont ||= []) << line
       next